Complex sentence: Hart worked briefly at the Giorgio Gianetti Architectural Plaster Studio in 1966, and assisted sculptor Felix de Weldon before taking a job as a mail clerk at the Washington National Cathedral, where he convinced master stone cutter Roger Morigi to offer him an apprenticeship in stone carving.
Split into simpler sentences: Hart worked briefly at the Giorgio Gianetti Architectural Plaster Studio in 1966, and assisted sculptor Felix de Weldon before taking a job as mail clerk at the Washington National Cathedral. Once there, he convinced master stone cutter Roger Morigi to offer him an apprenticeship in stone carving.