Complex sentence: For a full three days Mrs. Michieli tried to force the issue, but the superior of the institute for baptismal candidates (Catechumenate) that Bakhita had attended, complained to the authorities.
Split into simpler sentences: For a full three days Mrs. Michieli tried to force the issue. So, the superior of the institute for baptismal candidates (Catechumenate) that Bakhita had attended complained to the authorities.