Complex sentence: St. Alphonse spent several years of his religious life during the 18th century in Deliceto and, while there, wrote a popular Christmas Carol "Tu scendi dalle stelle" (You came down from the stars).
Split into simpler sentences: St. Alphonse spent several years of his religious life during the 18th century in Deliceto. While there, he wrote a popular Christmas carol "Tu scendi dalle stelle" (You came down from the stars).