Soshinni preached Zen even to Iemitsu, and soon after that he donated the land which was the site of residence of Ryukei OHASHI, a former private secretary of the bakufu, to Soshinni and instructed to erect a temple, and thereby the Saisho-ji Temple was erected with Soshinni as its kaiki.
祖心尼は、家光にも禅を説き、やがて、家光は祖心尼に幕府祐筆の大橋龍慶屋敷跡を寺領を寄進して寺院建立を指示し、祖心尼を開基として済松寺が建立される。