Complex sentence: Although he was busy with other projects and was at first unimpressed by the proposal, on a later visit to the city he was immediately impressed by the visual grandeur of the city's skyline, and agreed to perform.
Split into simpler sentences: Although he was busy with other projects and was initially unimpressed by the proposal, he later visited the city. He was immediately impressed by the visual grandeur of the city's skyline, and agreed to perform.