After the deaths of Charles V and du Guesclin in 1380, France lost its main leadership and overall momentum in the war. Charles VI succeeded his father as king of France at the age of 11, and he was thus put under a regency led by his uncles, who managed to maintain an effective grip on government affairs until about 1388, well after Charles had achieved royal majority. With France facing widespread destruction, plague, and economic recession, high taxation put a heavy burden on the French peasantry and urban communities. The war effort against England largely depended on royal taxation, but the population was increasingly unwilling to pay for it, as would be demonstrated at the Harelle and Maillotin revolts in 1382. Charles V had abolished many of these taxes on his deathbed, but subsequent attempts to reinstate them stirred up hostility between the French government and populace. Difficulties in raising taxes and revenue hampered the ability of the French to fight the English. At this point, the war's pace had largely slowed down, and both nations found themselves fighting mainly through proxy wars, such as during the 1383-1385 Portuguese interregnum. The independence party in the Kingdom of Portugal, which was supported by the English, won against the supporters of the King of Castile's claim to the Portuguese throne, who in turn was backed by the French.

How many years did the Portuguese interregnum last?
2