Complex sentence: The "Flying Cloud" of 1851 was the most famous of the extreme clippers built by Donald McKay in East Boston, Massachusetts, intended for Enoch Train of Boston, who paid $50,000 for her construction.
Split into simpler sentences: The "Flying Cloud" of 1851 was the most famous of the extreme clippers built by Donald McKay. She was built in East Boston, Massachusetts, and intended for Enoch Train of Boston, who paid $50,000 for her construction.