When in 1896 he founded a contemplative Congregation, Adolfine Tönnies belonged to the founding Sisters of this community of the “Servants of the Holy Spirit of Perpetual Adoration,” whose superior and later Superior General she became.
As a Sister she received the religious name Mary Michael. Although she lived in an enclosed cloister, she was with all her heart a missionary as well. She worked for the inner and outer development of her Congregation and founded new adoration convents in Germany, the Netherlands, the USA, the Philippines and China.
She died on February 25, 1934 in the Motherhouse in Steyl, Netherlands