The involvement of England in the History of Portugal, during the period associated with the Battle of Aljubarrota (1385).

The One Hundred Years War, between England and France, began in 1337. Once this
war began, the Castilian Kingdom became the main all
y of France. Portugal, independent
since 1144, had within the context of this War an important strategic position, since it
represented the west flank of the European conflict.

In 1367, D. Fernando became King of Portugal. After 1369, D. Fernando e
ngaged in three wars
with Castile, as he considered himself entitled to the throne of Castile, since he was the great
grandson of D. Sancho, the Brave , a previous King of Castile. For this purpose, he had the
support of several noblemen from Galicia. Withi
n the context of these wars, in July 1371, D.Fernando signed the Treaty of Tagilde with John of Gaunt, the Duke of Lancaster, who was the
third son of Edward III, King of England. This Treaty was a political and military alliance between
Portugal and Eng
land against Castile. John of Gaunt was married to D. Constanza, daughter of
the previous King of Castile, D. Pedro I, and therefore considered himself to be entitled to the
throne of Castile. He also wanted to attack Castile, as the present king, D. Henri
que II, had killed his wife’s father, D. Pedro I.
The Treaty of Tagilde prompted an invasion of Portugal by Henrique II, King of Castile, in 1372.
Lisbon was besieged and partly occupied for a month. After several negotiations, King D.
Fernando agreed to
support Castile and France, in the One Hundred Years War.
However, in 1380, D. Fernando made a new agreement with Edmund, the Count of Cambridge,
son of Edward III, and therefore brother of the Black Prince, and of the Duke of Lancaster. Under
this agre
ement, D.Beatriz, the only daughter of D. Fernando, would marry Edward of Langley,
the son of the Count of Cambridge. This enabled an English fleet of 48 ships, to transport 1.000
archers and 2.000 armed men to Portugal, which disembarked in Lisbon in July
1381. This was
the first time in history that England had a military presence in Portugal. With these men came,
not only Edmund of Cambridge and his family, but also experienced captains from the One
Hundred Years War, and several figures from the English
Court. This army marched to the border of Portugal with Castile, in Alentejo and in July 1382, the Portuguese and the Castilian armies came face to face, near the River Caia. The One Hundred Years War was very apparent in this conflict, since the Portuguese King was supported by the said 3.000 English warriors, and many French cavaliers and footmen supported the Castilian King, D. Juan I. This battle did not
take place however, as Castile agreed to return several castles and all the Portuguese prisoners.
In return, D. Fernando agreed that his only daughter, D. Beatriz, would marry the King of Castile.

The Wonderful Story of Britain: The Bowmen of Britain. English longbowmen at the Battle of Crecy. Original artwork from Treasure no. 55 (1 February 1964).

This treaty was not well received by the English expeditionary force, which were expecting the
benefits of a military victory. It was also not welcomed by the
Portuguese people, who saw the
threat of a possible political union with Castile. Due to this treaty, the English expeditionary
force returned to England, in September 1382.
King D. Fernando died in October 1383. This created a period of political uncer
tainty, as the wife of the Castilian King, D. Beatriz, would be the Queen of Portugal. Also, the Castilian king began calling himself King of Portugal. With the general support of the Portuguese people, D. João,
Mestre de Avis, and brother of D. Fernando,tried to prevent the union of the kingdoms of
Portugal and Castile, and took possession of several cities, such as Lisbon and Oporto. Aware of
this unrest, the King of Castile, D. Juan I, invaded Portugal, in January 1384, in order to gain the
Portuguese throne.
Knowing that his military forces were still small, Mestre de Avis again tried to form an alliance
with England. Mestre de Avis knew that the Castilian fleet was supporting France in the One
Hundred Years War, and that it would be important for Eng
land to keep the Portuguese ports
open to English ships. In this context, Portugal could be an important ally of England, namely
due to its strong military fleet. Therefore, in February 1384, Mestre de Avis sent emissaries to
negotiate with Richard II, the
King of England, and with the Duke of Lancaster. At first, the
English leaders were reluctant to accept a new agreement, following the experience of the
English military expedition in 1381. However, in May 1384, a new agreement was reached, and
the Portuguese were given permission to recruit English archers and armed men, who would be
transported to fight in Portugal. In return, Portugal would send a squadron of galleys to be used
by England against France and Castile, and would also support a possible inv
asion of Castile by the Duke of Lancaster.

At the end of 1384, four experienced English squires were also contracted by Portugal. They
were Elie de Blythe, Robert Grantham, Peter Cressingham, and Reginald Cobham.
Due to the Castilian invasion of Por
tugal, Lisbon was under siege by the Castilian army and fleet,
between May and September 1384. However, due to Portuguese resistance, the Castilian army
returned home in September. During 1384 and 1385, several battles took place between the
Portuguese and
Castilian armies, throughout different parts of Portugal and Castile. In these
battles, a brilliant Portuguese commander, Nuno Álvares Pereira, was always successful.
In April 1385, the English mercenaries finally arrived in Portugal. According to a stu
dy conducted
by Prof. A. Stott Howorth, in 1960, these mercenaries were mainly from the middle and lower
social classes, some of them with reasons to leave England. However they were experienced
warriors, who had already fought in Portugal or in France. Th
ey were transported in four ships,
which sailed from Plymouth on the 24th
of March. These ships belonged to a Dartmouth ship
owner, Edmund Arnald, and they also carried wheat, and pork meat, for the supply of the
English armed men. These ships arrived in the ports of Oporto, Lisbon and Setúbal. Although the
two ships that arrived in Lisbon were attacked by twelve Castilian galleys, the English warriors
were able to disembark and join the Portuguese army.
Altogether, this transport included 650 men, of which approximately 450 were archers and 150 armed men. Due to an investigation undertaken in 1959 by Sir Peter E. Russell, from the University of Oxford, it is possible today to know the names of these Englishmen, through a
document called “Public Record Office”, written in the XIV century.
This group of English warriors was in accordance with the agreement signed, in 1384, between
the emissaries of Mestre de Avis and Richard II, King of England. Due to this agreement, Portugal
also sent six galleys to the River Thames, in order to protect London from a possible Castilian
attack. These ships were 40 meters long, 7 meters wide, and had each approximately 260 men
on board, including rowers and armed men. These Portuguese ships soon destroyed twenty
-four French merchant ships, showing their superior mobility and military power. This
Portuguese naval victory was a major reason for the naval agreement signed, in May 9
th 1386,between Portugal and England.
The English mercenaries arrived in Portugal in the same month as Mestre de Avis was elected
King, at the Courts of Coimbra. The English military force arrived in Portugal just when it was
most needed, as by then, it was already known that another Castilian invasion would take place,
and that a decisive occasion would occur in the military conflict between Portugal and Castile.
These mercenaries participated, most likely, in May 1385, in the northern campaign of Portugal,
conducted by D. João I, namely in the conquest of the castles of Guimarães and of Ponte de Lima.
In June 1385, D. Juan I of Castile invaded Portugal, through the city of Guarda, with an army of
42.000 men. This army included 2.000 French cavaliers, which the Castilian King received from
France, as a result of its involvement in the One Hundred Years War.The Portuguese war council held a meeting, on August 8th, in Abrantes, 100 Km outside Lisbon,to discuss its strategy. Nuno Álvares Pereira argued that a decisive battle should be forced, since Lisbon would not be able to sustain a siege from such a strong Castilian army. He declared that
the help of the English archers would be an important factor. Although an immediate
agreement was not reached, the Portuguese decided, two days later, to fight a decisive battle
against the Castilians.
The Portuguese army, composed of approximately 8.000 men, then advanced to the fields of
Aljubarrota, in order to intercept the march of the Castilian army towards Lisbon. Most, if not all
of the English mercenaries then present in Portugal, took
part in this march. The Portuguese army, camped, on the 12th of August, outside the village of Porto de Mós, and on the 14th  of August, 1385, was located in the fields of Aljubarrota, where the decisive battle was about to take place.All the English archers were placed on the advance right wing of the Portuguese army, in order
to aim at the advancing French cavalry, and at the Castilian army. The effect of their arrows was
extremely important during the battle, since they could hit the enemy within a ran
ge of 350 meters. Each of these English archers was able to throw 12 arrows per minute. Since the archers
that were present in Aljubarrota were all very experienced, we can conclude that close to
200.000 arrows were released by these archers in the Battle
of Aljubarrota. This had a very significant effect on the outcome of the battle, since these arrows hit both horses and men of the advancing French-Castilian army, without distinction. The English archers and armed men
also played another important role in the battle. Once the advancing Castilians breached the
Portuguese vanguard, the English archers and armed men abandoned their initial positions, and
engaged in hand to hand fighting with the Castilian armed men. Through a hard battle, and
together with the Portuguese men, they were able to eliminate and drive back all the incoming
It must also be said that the tactic used by the Portuguese army, led by Nuno Álvares Pereira,
was greatly influenced by English warfare of the One Hundred Years War
. In effect, during previous periods of the Middle Ages, battles were decided by charges of heavy cavalry. After the XIV century, the English introduced the tactic of choosing the ground well, waiting for the
enemy with every man on foot, building obstacles such as pit holes, trees on the ground and
ditches, and profiting from the thousands of arrows released by the archers. The Portuguese
commander learned this new tactic well from the British army, while he was only a soldier in D.
Fernando’s reign. In effect, while living with the Count of Cambridge ́s army, during 1381 and
1382, Nuno Álvares Pereira was able to discuss this new tactic, and to analyse its effectiveness.
In the Battle of Aljubarrota, he applied this new tactic with perfection.
It was also due to the experience gained in the One Hundred Years War, why some of those
English armed men, present at the Battle of Aljubarrota, advised the King of Portugal to stop
pursuing the fleeing Castilians in the last moments of the battle. In effect,
to continue pursuing
the enemy could expose the Portuguese army to a dangerous Castilian counter attack. It was
therefore considered more appropriate to stay in the initial position, and assure a Portuguese
After seeing his army defeat, D. Juan I, King of Castile, returned home by sea. The rest of the
army, returned to Castile, through different routes. Never again would the King of Castile be
able to organize such a big army and invade Portugal.
The result of the Battle of Aljubarrota made a strong and durable alliance between Portugal and
England possible. With the news of this victory, the Portuguese ambassadors, who had been in
England for a year, could then propose to the English Court, a vast political and military alliance with the most western of the European countries–Portugal. Having legitimate claims to the
Castilian throne, John of Gaunt, Duke of Lancaster, then obtained permission from the King of
England, Richard II, to prepare for a significant military expe
dition to the Iberian Peninsula, in coordination with the Portuguese king.
In May 1386, the two kingdoms signed, in Windsor, a famous treaty, the Treaty of Windsor,
which was followed, a few months later, by the marriage of the Portuguese King, D. João I
, with the daughter of John of Gaunt, D. Philippa of Lancaster. D. Philippa was then the direct cousin of
the King of England, Richard II. Under this Treaty, both countries would defend each other, in
case of an attack, and commerce between the countries would be promoted. As mentioned before, England was then strongly involved in the One Hundred Years War, and was aware of the importance of the west flank of Europe. Portugal could be a very effective base for a strong attack against Castile, which was the most important French ally during the One Hundred Years War. Moreover, Richard II recognized the naval capability of the Portuguese, and did not underestimate the advantage that this could offer when facing, in French or English waters, the Castilian galleys that where placed at the disposal of France.
After the Battle of Aljubarrota, D. João I, King of Portugal, conquered several castles in the north
of Portugal, that were still loyal to Castile. However, he realised that to consolidate his victory
over Castile, he needed to keep military pressure on the Castilian Kingdom. He therefore agreed
to support the expedition of John of Gaunt, the Duke of Lancaster, to Castile. As mentioned
previously, John of Gaunt was married to D. Constanza, the daughter of the former King of Castile, D. Pedro I, and considered that he could claim the Castilian throne, for which he had the support of the Portuguese army. This invasion of Castile was also a consequence of the agreement signed between Portugal and England, in March 1384, which stated that Portugal would support a possible military campaign of John of Gaunt in Castile.
In July 1386, John of Gaunt disembarked in the north of Castile, in Corunha, leading a fleet of
100 ships, 12 of which were Portuguese. His army was 7.000 men strong. He came to Portugal,
were he met with the Portuguese king, at the Bridge of Mouro, near Monção. For this occasion,
John of Gaunt installed approximately one hundred tents around this bridge, with the colours of
England and of the Lancaster family. They agreed not only to a joint invasion of Castile, but also
to the marriage of D. João I, King of Portugal, with Philippa of Lancaster, daughter of John of
Gaunt. If the conquest of Castile was successful, John of Gaunt would give Portugal p
arts of Castile, situated near the border with Portugal.D. João I married Philippa of Lancaster in Oporto, in February 1387. After this ceremony, and the recruitment of the necessary troops, the joint invasion of Castile began on March of 1387. The Anglo-Portuguese army was composed of 12.000 men, of which 3.000 horsemen, 2.000 crossbow men, and 3.000 foot soldiers, were Portuguese.
The Anglo-Portuguese army took some small villages in the north of Castile, near Zamora and
Salamanca, between March and June 1387. However, the Castilian King, D. Juan I, who was
accompanied and advised by the French troops sent by Charles VI, avoided a direct battle,
preferring to stay within his castles. He also burned the fields in order to prevent the Anglo
-Portuguese army obtaining food. The Castilians often attacked the Anglo-Portuguese army with
guerrilla warfare.Lacking military success, and experiencing difficulty in feeding his troops, John of Gaunt opted to negotiate with the Castilian King, and returned to Por
tugal, to the village of Trancoso, in early June 1387. This agreement stated that Catalina, the daughter of John of Gaunt and of Constanza, would marry the elder son of the Castilian King, D. Henrique, becoming therefore
Queen of Castile. Also, the Castilian King paid John of Gaunt significant compensation. In order
to sing this agreement in the city of Bayonne, John of Gaunt embarked with his fleet in Oporto,
in September 1387.
The Castilian campaign, although gaining no major military success, had he
lped Portugal keep the Castilian army under pressure, and had prevented the Castilian king from trying to invade
Portugal again. After same years of combats, which included the Battle of Valverde, inside
Castile, the peace agreement was finally signed in 1411. Portugal had assured its independence.
Soon after, Portugal began the preparations for the conquest of Ceuta, a major Arab city in the
north of Africa. Philippa of Lancaster encouraged, and was very much in favour of this initiative.
Through the use
of a fleet of approximately 240 ships, including “naus” and galleys, Ceuta was
taken in 1415. The Portuguese maritime expansion had begun.
Relations between Portugal and England improved in the coming years. Several factors
contributed to this process.
Firstly, in political and military terms, the One Hundred Years War
was still evolving, and only ended in 1453, which encouraged both countries to cooperate
against its enemies, Castile and France. Secondly, economic and commercial relations increased,
due  to a strong naval presence, based on each country’s ports. Thirdly, the marriage of D. João I,
King of Portugal, with a member of the English royal family, also facilitated relations between
the two countries. An example of this was the decoration granted
, by Henry IV, King of England,
to D. João I, on the 23rd of April 1409, in Windsor Castle. D. João I received the highest English
insignias, which had never been given to a foreigner before.
It is also important to value the work done in Portugal, by the
Queen Philippa of Lancaster. She
was very kind and well educated, and had a strong character. As Queen of Portugal, she
improved and increased several buildings and monuments, such as the Sintra Palace, the
Monastery of Batalha, and the Palace within the
Castle of Leiria. D. Philippa also helped her husband in several ceremonies, and even presided over same official meetings. She paid great attention to her sons  education, even using some English teachers. The result was that her sons became extremely well educated, in areas such as mathematics, physics, literature or languages and became very creative and efficient throughout their professional careers. This fact was
evident in the reign of D. Duarte, who became King in 1433. The excellent education give
n to D.João and D. Philippa’s sons, certainly contributed towards the good government that Portugal
experienced in the coming decades.

The Battle of Aljubarrota marked a golden period for Portugal and England, and created the
basis for a strong alliance between the two countries. Due to this period, both countries became
allies throughout the coming centuries, as was the case in the Restoration War of Portugal
against Spain (1640–1667), in the Napoleonic Wars (1789
–1815), the First World War (1914–1918) and in the Second World War (1939–1945). Apart from the military alliance, since 1385,both countries were able to establish an open and trusting relationship, in both the political and economic areas, that still prevails today.
The result of the Battle of Aljubarrota was one of the most important events in the History of
Portugal. It enabled this country to become free and independent, it assured the beginning of
the Portuguese second dynasty, the Avis Dynasty, and made possible th
e preparation of the most brilliant period of national history, the period of the Maritime Discoveries.
Aljubarrota therefore bestowed, both directly and indirectly, a new dimension to the
History of Portugal and to the World itself, with an extraordinary
influence that would last throughout the centuries.With its relevant participation in events of this period, as well as in the Battle of Aljubarrota, England made a significant contribution to the successful results achieved, and became associated, forever, with the History of Portugal.