So it is not strange if he signed an alliance with France, and entered the Hundred Years War in the French side of the same one. Enrique sent a fleet, commanded by the Genoese Ambrosio Bocanegra, to attack the English at La Rochelle, city besieged by French. The English defending fleet was commanded by John of Hastings, count of Pembroke. On June 22th 1372, both fleets clashed, with disastrous results for English. Like in Winchelsea .
Chronicles are also contradictory.
Castilian navy was surprised by English, but reacted and its bigger ships managed to impose over the English, capturing a couple of ships. During the night, Pembroke tried to look for help in the city, without success. For the French De la Ronciere, Bocanegra took profite of the faster velocity if his ships, as well as their lower draft, in order to make English ships run aground, and attack them later, capruting all of them in an overwhelming victory. Finally, the Spanish L pez de Ayala affirms the twelve Spanish ships attacked the English, capturing Pembroke with all his knights and ships. Even more, in his return to Spain, Bocanegra captured 4 aditional English ships.