Complex sentence: The neighborhood that is now called Capitol Hill began when the government began work at two locations, the U.S. Capitol and the Washington Navy Yard, and came to be a distinct community between 1799 and 1810 as the federal government became a major employer.
Split into simpler sentences: The neighborhood that is now called Capitol Hill began when the government began work at two locations, the U.S. Capitol and the Washington Navy Yard. It became a distinct community between 1799 and 1810 as the federal government became a major employer.