In 1876, Lainhart homesteaded land that includes the entire historic district north of Belvedere Road.

In 1883, she officially homesteaded land that includes the entire historic district south of Belvedere Road.

During the 1920s, Pittsburgh socialite Jay Phipps, the son of Andrew Carnegie's partner in U.S. Steel, assembled the old pineapple fields and other property to develop the historic district.

Phipps named this development of predominantly Spanish-style homes El Cid after the celebrated Spanish hero, Rodrigo Diaz de Bivar (1040–1099), who led Castilians and Iberian Moors to conquer Valencia in 1094.

Moors called him “Cid” an Arabic term meaning “lord.” The neighborhood's proximity to downtown and the western shore of Lake Worth attracted affluent business, political and social leaders who dominated the community's development in the 1920s and 1930s.