Complex sentence: He was particularly impressed by the works of Fra Angelico and Giotto in San Marco, and Tintoretto in the Scuola di San Rocco but was alarmed by the combined effects of decay and modernisation on Venice: "Venice is lost to me," he wrote.
Split into simpler sentences: He was particularly impressed by the works of Fra Angelico and Giotto in San Marco, and Tintoretto in the Scuola di San Rocco. But he was alarmed by the combined effects of decay and modernisation on Venice: "Venice is lost to me," he wrote.