Complex sentence: He was born in San Matteo della Decima, near Bologna, to a family of painters including Mauro & Ubaldo Gandolfi, and became a "student" at the Accademia Clementina in Bologna, where he was taught by Felice Torelli and Ercole Lelli.
Split into simpler sentences: He was born in San Matteo della Decima, near Bologna, to a family of artists. Gaetano became a "student" at the Accademia Clementina in Bologna, where he was taught by Felice Torelli and Ercole Lelli.