Gregorious de Cespedes was a Portuguese

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

 priest

Priest

A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

 who went to Korea

Korea

Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

 to do missionary

Missionary

A missionary is a member of a religious group sent into an area to do evangelism or ministries of service, such as education, literacy, social justice, health care and economic development. The word "mission" originates from 1598 when the Jesuits sent members abroad, derived from the Latin...

 work. He accompanied the forces commanded by Daimyo Konishi Yukinaga

Konishi Yukinaga

Konishi Yukinaga was a Kirishitan daimyō under Toyotomi Hideyoshi. He was the son of a wealthy Sakai merchant, Konishi Ryūsa...

, himself a Christian, and proselytized among the Japanese soldiers. There is little evidence that he interacted directly with the Korean population, but it is believed that he did proselytize among Koreans held captive by the Japanese.