But now, according to the head of the association representing Europe's biggest clubs, a third European competition is set to be introduced again.
It was an idea first put forward in 2015 and should offer more chances for Scottish clubs to progress in European football.
The new competition will bring the overall number of clubs involved in European football to 96.
Agnelli sits on the UEFA executive committee and is also the chairman of Italian club Juventus.
All three subjects are part of FIFA-led talks to agree on a new global calendar beyond 2024 - the year when widespread changes to soccer can take effect, Agnelli has said.
UEFA has made little secret of the fact that it has been looking at ways to raise the Europa League's profile while also giving more clubs a shot at European competition, and therefore its growing financial benefits.
The Champions League and Europa League might not be enough for UEFA.
"It is nearly obvious that a third competition will be added". This would increase the number of clubs competing in Europe from 80 to 96.
Agnelli, also the president of Serie A champions Juventus, called for "more global [European] games and less domestic" matches earlier this year.
It could mean the Europa League's group stage will be trimmed from 48 teams to 32, with the third European club competition, the Champions League and the Europa League having the same number of participants.
Back then, UEFA president Aleksander Ceferin said proposals were "just discussions".