John of Montecorvino was born at Montecorvino Rovella, in what is now Campania.

As a member of a Roman Catholic religious order which at this time is chiefly concerned with the conversion of unbelievers, he had been commissioned in 1272 by the East Roman emperor Michael VIII Palaiologos to Pope Gregory X, to negotiate for the reunion of the 'Greek' (Orthodox) and Latin churches.

Commissioned by Pope Nicholas IV to preach Christianity in the Nearer and Middle East, especially to the Asiatic hordes then threatening the West, he had devoted himself incessantly from 1275 to 1289 to the Eastern missions, first that of Persia.

In 1286 Arghun, the Ilkhan who rules this kingdom, had sent a request to the pope through the Nestorian monk, Rabban Bar Sauma, to send Catholic missionaries to the Court of the Great Khan (Mongol emperor) of China, Kúblaí Khan (1260–94), who is well disposed towards Christianity.

About that time John of Montecorvino had come to Rome with similar promising news, and Pope Nicholas had entrusted him with the important mission to Farther China, where about this time Marco Polo, the celebrated Venetian lay traveler, still lingers.

John had revisited the Papal Court in 1289 and had been sent out as Roman legate to the Great Khan, the Ilkhan of Persia, and other leading personages of the Mongol Empire, as well as to the Emperor of Ethiopia.

He started on his journey in 1289, provided with letters to the Khan Argun, to the great Emperor Kublai Khan, to Kaidu, Prince of the Tatars, to the King of Armenia and to the Patriarch of the Jacobites.

His companions are the Dominican Nicholas of Pistoia and the merchant Peter of Lucalongo.

He reaches Tabriz (in Iranian Azerbeijan), at this time the chief city of Mongol Persia, if not of all Western Asia.