Religion was the most common subject of his paintings, as the church was the most important art patron in Rome and because there was a growing demand by wealthy patrons for devotional paintings at home. He took a large part of his themes from the Old Testament, which offered more variety and the stories were often more vague and gave him more freedom to invent. He painted different versions of the stories of Eliazer and Rebecca from the Book of Genesis and made three versions of "Moses saved from the waters". The New Testament provided the subject of one of his most dramatic paintings, "The Massacre of the Innocents", where the general slaughter was reduced to a single brutal incident. In his "Judgement of Solomon" (1649), the story can be read in the varied facial expressions of the participants.