The ancestors of William Fiennes (1357-1402) ties to the line of Margaret Fiennes (1269-1334) with the grandparents of Margaret and the great great grandparents of William. Those common ancestors are Enguerrand Fiennes and Isabel Conde. See https://fabpedigree.com/s048/f082772.htm and https://fabpedigree.com/s077/f375094.htm

Historical
1360: England, France - Treaty of Calias, England and France sign a treaty on October 24th, John II of France is ransomed and Edward III renounces his claim to the French throne
1364: Uzbekistan - Timur (Tamerlane) captures Samarkand (Uzbekistan)
1368: China - Chu Yuan-chang, a Han Chinese peasant and former Buddhist monk who had become a rebel army leader, emerged as successor to Kublai Khan, founding the Ming dynasty, with a capital at Nanking
1369: Netherlands - Amsterdam joins Hanseatic League
1371: Turkey, Bulgaria - Serbs defeated by Ottoman Turks at Maritsa River (Bulgaria)
1372-1375: England, France - Hundred Years War resumes when the French fleet defeats the British fleet off La Rochelle y France, the French are helped by a powerful fleet from Castile, the Truce of Bruges is signed on June 27, 1375 limiting British presence in France to Calia, Brest, Bordeaux and Bayonne
1381: England - The Peasants Revolt led by Wat Tyler create anarchy throughout England burning a number of public buildings and beheading the archbishop of Canterbury, King Richard puts down the riot and Tyler is killed
1381: Italy - War of Chioggia, Venetian fleet under Vittoria Pisano defeat the Genoans, It begins the golden age of Venice
1384: Uzbekistan - Timur captures Herat, Sistan, Rayy, and Il-Khanid (the capital of Sultaniyeh)
1385: Portugal - Battle of Aljubarrota (central Portugal), Portugese under King John I defeat the Crown of Castile under King John I and his allies, the victory makes Portugal an Independent country
1389: Turkey - Turkish army under Sultan Murad I defeats Serbs under Prince Lazar at Kossovo Field (meaning "field of the black birds"), bringing Turkish rule to the area which lasts until the Balkan War of 1913, just before the battle, a Serb posing as a deserter brought before Sultan Murad produces a dagger and stabs the Sultan to death, he is Immediately killed, as is Serb leader Lazar who is captured in the battle
1392: China - Yi Songgye, with the aid of the Ming rulers of China, seize the Korean throne from the Koryo dynasty, the Yi dynasty lasts until 1910
1395: Mongolia - Timur sacks Sarai Berke, ending central control of the Mongol Golden Horde
1396: Turkey, Hungary - Ottomans defeat Hungarians at Nicopol
1397: Sweden, Norway, Denmark - Magaret, Queen of Sweden, conquers Denmark and Norway then forms the Kalamar League, a union of all three countries
1398: Mongolia, India - Timur sacks Delhi, causing demise of the Delhi Sultinate, founded back in 1192
1400: Indonesia - Paramesvara founds the Kingdom of Malacca on the Malay peninsular (Indonesia), It soon becomes the leading maritime power in South East Asia
1400: Mongolia, Syria, Russia, Georgia, Iraq - Mongol conqueror Timur Invades Syria after devastating Georgia and Russia, the next year he lays waste to Aleppo, Damascus and Baghdad and the year after that e defeats the Ottoman sultan at the Battle of Angora
1402: Mongolia, Turkey - Timur captures Ottoman Turk Sultan Beyazid I at Angora