Complex sentence: Sixtus of Siena or Sixtus Senensis (1520-1569) was a converted Jew who followed a Franciscan course of study and became a Roman Catholic theologian, one of the two outstanding Dominican scholars of his generation.
Split into simpler sentences: Sixtus of Siena or Sixtus Senensis (1520-1569), a converted Jew, followed a Franciscan course of study and became a Roman Catholic theologian. He is considered one of the two outstanding Dominican scholars of his generation.