S.L. Benfica 2015, Benfica reported to have 246,401 members; however, after a scheduled renumbering by the club in August 2015, the number decreased to 156,916. In April 2017, Benfica reported they had a total of 184,264 members by 31 December 2016. Benfica has rivalries with Sporting CP and FC Porto, with whom it forms the "Big Three": Portugal's most decorated clubs. None of them have been relegated from the Portuguese league since its establishment in 1934. As Lisbon-based clubs, Benfica and Sporting have shared a rivalry for over a century; it all started in 1907 when eight prominent Benfica players defected to
FC Porto in international football competitions losing the 1964 Portuguese Cup final against champions Benfica. Porto progressed from the first round of a European competition for the first time, after a 4–0 aggregate victory over French Cup winners Lyon, but fell in the next round to 1860 Munich.<ref name="1964/65"></ref> At the end of that season, Porto finished runners-up to Benfica in the league and qualified for the following season's Fairs Cup. The club's performance was similar to that of the previous campaign: a first-round elimination of a French team (Stade Français) followed by a second-round loss to a German team (Hannover 96),<ref name="1965/66"></ref> which included a