January 2016: FIFA imposes 2 transfer window ban on Real Madrid & Atletico Madrid.
(on hold pending appeals)
December 2016: Real ban cut to 1 window by Court of Arbitration for Sport, only applied January 2017.
2017: CAS upheld Atletico's 2-window ban which covered Jan & summer

— Rob Harris (@RobHarris) February 22, 2019