Harunobu was born in
Hinoe Castle, the
Arima clan castle that controlled the
Shimabara area of
Hizen Province. He was the second son and successor of
Arima Yoshisada. After Yoshisada's death, he began the persecution of
Kirishitan in his region. With
Ryūzōji Takanobu expanding into his domain, Harunobu turned to the help of the
Jesuits. Harunobu was baptized by
Alessandro Valignano in 1579. His conversion was spurred by the prospects of the goods and military assistance offered by the Portuguese. He took the
baptismal name Protasius, and later took the name John when he received
Confirmation. As a result of his conversion to Christianity, Harunobu started to receive weapons from the
Portuguese, which strengthened the
Arima clan. Harunobu also founded a
seminary and training center for
novices in his domain where, apart from the ordinary curriculum, students were also taught European music, painting and sculpture and the manufacture of
organs and
pocketwatch. Soon after the conversion, Harunobu and the Jesuits ordered the destruction of over 40 Buddhist and Shinto temples and shrines in the domain, along with the forced evictions of Buddhist monks. Before their destruction, the temples and shrines were said to be some of the most stunning and famed in all of Japan. When
Toyotomi Hideyoshi expelled the
Catholic fathers and outlawed the teaching of
Christianity in 1587, the Arima domain became a refuge for many Christian missionaries and believers. After
Kyūshū was invaded in 1587, Harunobu allied with
Toyotomi Hideyoshi. During the year 1592, the allied force led some 2,000 men to Korea under
Konishi Yukinaga. During the
Battle of Sekigahara in 1600, Harunobu supported
Tokugawa Ieyasu, and thus did not lose any land after the battle. ==Okamoto Daihachi incident==