May 21, 2013 NYCFC is announced as the 20th team in MLS via a partnership between City Football Group and Yankee Global Enterprises.
https://www.nycfc.com/post/2017/05/21/nycfc-celebrates-founding-day-anniversary
https://www.nycfc.com/post/2017/05/21/nycfc-celebrates-founding-day-anniversary