Complex sentence: According to musicologist Richard Kassel, the French organ builder Aristide Cavaillé-Coll proposed a giant swallow's nest organ for St Peter's Basilica in Rome in 1869 and spent the rest of his life trying unsuccessfully to have his plan approved by the Vatican.
Split into simpler sentences: According to musicologist Richard Kassel, in 1869 the French organ builder Aristide Cavaillé-Coll proposed a giant swallow's nest organ for St Peter's Basilica in Rome. He spent the rest of his life trying unsuccessfully to have his plan approved by the Vatican.