The Japanese Embassy went on to Italy where they were able to meet with Pope Paul V in Rome in November 1615, the same year Galileo Galilei was first confronted by the Roman Inquisition regarding his findings against geocentricism. Hasekura remitted to the Pope two gilded letters, one in Japanese and one in Latin, containing a request for a trade treaty between Japan and Mexico and the dispatch of Christian missionaries to Japan. These letters are still visible in the Vatican archives. The Latin letter, probably written by Luis Sotelo for Date Masamune, reads, in part:
Kissing the Holy feet of the Great, Universal, Most Holy Lord of The Entire World, Pope Paul, in profound submission and reverence, I, Idate Masamune, King of Wôshû in the Empire of Japan, suppliantly say:
The Franciscan Padre Luis Sotelo came to our country to spread the faith of God. On that occasion, I learnt about this faith and desired to become a Christian, but I still haven't accomplished this desire due to some small issues. However, in order to encourage my subjects to become Christians, I wish that you send missionaries of the Franciscan church. I guarantee that you will be able to build a church and that your missionaries will be protected. I also wish that you select and send a bishop as well. Because of that, I have sent one of my samurai, Hasekura Rokuemon, as my representative to accompany Luis Sotelo across the seas to Rome, to give you a stamp of obedience and to kiss your feet. Further, as our country and Nueva España are neighbouring countries, could you intervene so that we can discuss with the King of Spain, for the benefit of dispatching missionaries across the seas." Translation of the Latin letter of Date Masamune to the Pope.
The Pope agreed to the dispatch of missionaries, but left the decision for trade to the King of Spain.
The Roman Senate also gave to Hasekura the honorary title of Roman Citizen, in a document he brought back to Japan, and which is preserved today in Sendai.
Hasekura conversing with the Franciscan Luis Sotelo, surrounded by other members of the embassy, in a fresco showing the "glory of Pope Paul V". Sala Regia, Quirinal Palace, Rome, 1615.
Sotelo also described the visit to the Pope, book De ecclesiae Iaponicae statu relatio (published posthumously in 1634):
"When we got there by the aid of God in the Year of Our Salvation 1615, not only were we kindly received by His Holiness the great Pope, with the Holy College of the Cardinals and a gathering of bishops and nobles, and even the joy and general happiness of the Roman People, but we and three others (whom the Japanese Christians had specially designated to announce their condition with respect to the Christian religion) were heard, rested, and just as we were hoping, dispatched as quickly as possible." (Sotelo, De ecclesiae Iaponicae statu relatio).