He was in Venice in April 1400, then overland to Milan where he met with Duke Gian Galeazzo Visconti, son of the man whose daughter married Lionel of Antwerp (Chaucer was in the embassy that arranged it).
There was another man in Milan whom Manuel knew: his close friend and ambassador to Italy, Manuel Chrysolaros. Chrysolaros had been there for a few years and well-respected as a scholar and a sour ce of knowledge about Greek culture.
Manuel then went to Charenton in northern France where he met with King Charles VI on 3 June. Michel Pintoin (c.1350 - c.1421), the "Chronicler of St.-Denis," recorded their meeting:
Then, the king raised his hat, and the emperor raised his imperial cap – he had no hat – and both greeted one another in the most honourable way. When he had welcomed [the emperor], the king accompanied him into Paris, riding side by side. They were followed by the Princes of the Blood who, once the banquet in the royal palace finished, escorted [the emperor] to the lodgings which had been prepared for him in the Louvre castle.
Manuel spent summer and fall in France, leaving in December for England. His earlier entreaties for aid had been rebuffed by Richard II of England due to internal struggles, but those struggles ended when Henry IV became king. (The illustration shows the two meeting.) The meeting between Henry and Manuel—the first and only presence of a Byzantine Emperor in England—was recorded by contemporary writer Thomas Walsingham:
At the same time the Emperor of Constantinople visited England to ask for help against the Turks. The king with an imposing retinue, met him at Blackheath on the feast of St Thomas [21 December], gave so great a hero an appropriate welcome and escorted him to London. He entertained him there royally for many days, paying the expenses of the emperor's stay, and by grand presents showing respect for a person of such eminence.
Manuel received £2000 (the receipt exists) from Henry. A joust was held in his honor in February 1401. The emperor wrote to his friend in Milan, Manuel Chrysolaros, about progress in finding aid against the Turks:
A large number of letters have come to us from all over bearing excellent and wonderful promises, but most important is the ruler with whom we are now staying, the king of Britain the Great, of a second civilized world, you might say, who abounds in so many good qualities and is adorned with all sorts of virtues.
...
And now, in accord with his nature, he has made himself a virtual haven for us in the midst of a twofold tempest, that of the season and that of fortune, and we have found refuge in the man himself and his character.
Manuel also gifted Western Europe with treasures from Constantinople. A piece of the tunic of Christ was sent to Pope Boniface IX, along with the Holy Sponge.
Ultimately, Manuel's efforts did not bear fruit. Bayezid was defeated by Tamerlane, the Turco-Mongol warrior who was expanding his own base. Constainople would eventually fall to the Turks in 1453, a couple decades after Manuel's death.
But let's talk about that Holy Sponge, and maybe some of the other relics of Christ's life that were important objects throughout the Middle Ages.