Complex sentence: When he returned to the U.S in the early 1900s he purchased a townhouse on East 19th Street, decorated it with his own works, and called it his House of Fantasy that became a social center for New York's art community.
Split into simpler sentences: When he returned to the U.S in the early 1900s he purchased a townhouse on East 19th Street, decorated it with his own works, and called it his House of Fantasy. The townhouse became a social center for New York's art community.