In which decade was the FA Football League founded?

The Football League was founded in the 1880s, specifically in 1888.

The competition was formally created and named the Football League at a meeting in Manchester on April 17, 1888. Aston Villa director William McGregor was the driving force behind the idea, which aimed to give professional clubs a reliable schedule of fixtures and income.

The inaugural season began on September 8, 1888, with twelve clubs from the Midlands and northern England. The founding members included Aston Villa, Everton, Blackburn Rovers, Preston North End, and Wolverhampton Wanderers. Each club initially played the others twice, once at home and once away.

Preston North End won the first championship in 1888–89 without losing a match, earning the nickname "the Invincibles." The Football League remained England’s top-level competition until the leading clubs formed the Premier League in 1992. It was later renamed the English Football League in 2016, but its origin remains firmly in the 1880s.