Complex sentence: Andrea Pozzo (Trento, 1642--1709) is best known for his masterpiece of fresco illusionist quadratura, the nave ceiling of the Church of Sant'Ignazio in Rome.
Split into simpler sentences: Andrea Pozzo (Trento, 1642--1709) is best known for his grandiose frescoes using illusionist technique calledquadratura. His masterpiece is the nave ceiling of the Church of Sant'Ignazio in Rome.