Towards the end of the 16th century, four Japanese boys began a trip to Europe. Their names were Itō Mancio, Chijiwa Miguel, Nakaura Julião and Hara Martinho. They had received schooling in subjects such as Japanese, Latin, music, and fine arts at the “seminario” in Arima. The Jesuit missionary Alessandro Valignano, who was responsible for overseeing Christian missionary activities in Japan, planned a big project whereby these four boys (representing Arima Harunobu as well as two other well-known Christian feudal lords) would be granted an audience with the Pope in Rome.

In 1582, the four boys departed Japan from Nagasaki. After a boat trip which took approximately half a year, they finally arrived in Lisbon, Portugal. They were granted audiences with such people as the King of Spain and two different popes, and were given a warm reception everywhere. They were also given citizenship of Rome, visited various countries, and were the topic of conversation topic across Europe. When they returned to Japan it had been eight years since their departure.

According to the missionary Frois’ History of Japan, the Pope in Rome entrusted the four ambassadors with gifts for Arima Harunobu, including a cross containing a relic of the true cross, a sword and a hat. These were presented to him at a church close to Hinoe castle.