Complex sentence: The library was founded in 1914 in the Briarcliff Community Center, and as the Briarcliff Free Library around 1921, then an association library within the New York State library system.
Split into simpler sentences: The library was founded in 1914 in the Briarcliff Community Center. Around 1921, the library was established as the Briarcliff Free Library, an association library within the New York State library system.