Complex sentence: As a votive offering for escape from the pestilence, the Republic of Venice vowed a church to Our Lady of Health (or of Deliverance,), and in 1631 it began the erection of the existing building.
Split into simpler sentences: As a votive offering for escape from the pestilence, the Republic of Venice vowed a church to Our Lady of Health (or of Deliverance,). In 1631 it began the erection of the existing building.