A Christian feudal lord
During the Warring States period, feudal lords in Japan were competing against one another and were therefore eager to attract Portuguese trade. This provided an opportunity for Christianity to be spread within their domains.
In 1543, a new dawn broke when a Portuguese ship landed in Tanegashima and introduced firearms to Japan. The power of the Muromachi shogunate had weakened, and the age where feudal lords were competing against one another had started to arrive (in Japanese history, this is known as the "Warring States" period). These feudal lords wished to attract foreign trade to their domains, hoping to obtain weapons and financial wealth. Among them was Arima Harunobu (feudal lord of the Arima clan), who held power throughout the Shimabara peninsular and whose headquarters was Hinoe castle.
Trade with Portugal came with a condition: that Christian missionary work be permitted within the domain in question. Harunobu granted the Jesuits his approval in this regard and received baptism, taking the baptismal name Don Protaçio. Later, the Christian missionary Frois wrote in his work History of Japan that thanks to the support which the Arima clan had received from the Jesuits, it was able to resist multiple attacks from a neighbouring feudal lord in Saga named Ryūzōji Takanobu, who was looking to increase his power.