There are 41 active Broadway theaters listed by The Broadway League in New York City. The definition of what constitutes a Broadway theater has changed multiple times; the current legal definition is based on a 1949 Actors' Equity agreement with smaller theaters in New York to allow union members to perform, dividing theater spaces in the city into the system of Broadway and Off-Broadway seen today. The general rule is that any venue that mostly hosts legitimate theater productions, is generally within Manhattan's Theater District, and has a capacity over 500 seats is considered a Broadway theater.