His uncle, Guichard did not have lands to tie him to France, and as soon as war with the English calmed during the 1380s, he left to fight in Hungary. In 1395, Guichard went on a crusade against the Ottoman Turks who had captured Constantinople. He was with the army defeated at the siege of Nicopolis in 1396. It took two years, and a great deal of ransom money to bring the survivors home. In 1400, he left with a second expedition led by Marshal Boucicault de Genes to aid the Eastern Emperor, Manuel II. They sailed into the Golden Horn in 1400 with 1,400 men-at-arms just in time to save Galata from the Turks. They were besieged in Constantinople for two years. In a naval battle, Guichard de la Jaille was again noted in dispatches for his bravery and courage. He returned to France in 1405 and died the following year.