associations in not participating in the All-Ireland Senior Football Championship. The Provincial Championships operate through a knock-out cup competition format. Historic format (1888–2000) For the first All-Ireland championship in 1887, the competition was played on an open draw knockout basis. From 1888, the provincial system was introduced, whereby the counties in each of Ireland's four provinces would play each other on a knockout basis to find provincial champions. These four champions would meet in the All-Ireland semi-finals. The structure outlined above was adopted in 2001 to allow more games to be played, but still retain provincial championships and the knockout structure, resulting in every game continuing to be a meaningful fixture, with no dead-rubber league format matches being played out. Quarter-finals format (2001–2017) From 2001 to 2017, the Championship was played using the Quarter-finals format. Under this format, Provincial matches would take place during the months of May, June and July. The winners of each of the four Provincial Championships would earn a place in the All-Ireland Quarter-Finals, which would take place in the month of August. Replays would be played for all drawn matches, not just drawn Provincial Finals and drawn All-Ireland Finals. Extra-time would only be used for Replays and Qualifier Matches. If the teams were still level after extra time, the qualifier match would go to a replay or in the case of replays, another replay would take place. The qualifiers series (also referred to as the "back door") for teams that did not win their provincial championships would take place in the months of June and July with the winning four teams of Round 4 playing the four Provincial Champions in the All-Ireland Quarter Finals. All-Ireland Quarter-Finals: The four Provincial Champions would be drawn against the winning four teams from Round 4 of the All-Ireland Qualifiers. If a match finished with both teams level, a replay would take place. The four winning teams qualify for the All-Ireland Semi-Finals. All-Ireland Semi-Finals: The All-Ireland Semi-Finals would take place in August and be contested by the four winners of the All-Ireland Quarter Finals. If a match ended with both teams level, a replay would take place. The two winning teams qualify for the All-Ireland Final. All-Ireland Final: The two remaining teams would meet in the All-Ireland Final, usually on the third Sunday in September. The winning team is crowned All-Ireland Champions. Single-tier championship format (2018–2019) This championship was identical