Complex sentence: Sister Marie de Mandat-Grancey was named Foundress of Mary's House by the Catholic Church and was responsible for acquiring, restoring and preserving Mary's House and surrounding areas of the mountain from 1891 until her death in 1915.
Split into simpler sentences: Sister Marie de Mandat-Grancey has been named Foundress of Mary's House by the Catholic Church. She is responsible for acquiring, restoring and preserving Mary's House and surrounding areas of the mountain from 1891 until her death in 1915.