NFL–AFL merger

The AFL–NFL merger was the merger of the two major professional American football leagues in the United States at the time: the National Football League (NFL) and the American Football League (AFL). It paved the way for the combined league, which retained the "National Football League" name and logo, to become one of the most popular sports leagues in the United States. The merger was announced on the evening of June 8, 1966. Under the merger agreement, the leagues maintained separate regular-season schedules for the next four seasons — from 1966 through 1969 — and then officially merged before the 1970 season to form one league with two conferences.

Since its inception in 1920, the NFL fended off several rival leagues. Before 1960, the most important rival was the All-America Football Conference (AAFC), which began play in 1946. The AAFC differed from the NFL in several ways, and the AAFC's perennial champions—the Cleveland Browns—were considered to be one of the best teams in professional football during that time.

Due to the AAFC's poor financial situation, however, the league disbanded after the 1949 season. Three AAFC teams—the Cleveland Browns, the San Francisco 49ers, and the original version of the Baltimore Colts—were absorbed into the NFL in 1950. The league was briefly known as the National-American Football League during the offseason, but reverted to the traditional name of "National Football League" by the time the 1950 season began.

After the NFL absorbed the AAFC, it went unchallenged by rival leagues until 1960. In 1959, Lamar Hunt, son of Texas oil magnate H. L. Hunt, attempted to either gain ownership of the Chicago Cardinals with Bud Adams and move them to Dallas, or own an NFL expansion franchise in Dallas. In 1959, the NFL had two teams south of Washington, D.C. and two teams west of Chicago (the San Francisco 49ers and the Los Angeles Rams, both in California). The league, however, was not interested in expansion at the time. Rebuffed in his attempts to gain at least part ownership in an NFL team, Hunt conceived the idea of a rival professional football league, the American Football League. In September 1959, Hunt was approached by the NFL about an expansion team in Dallas, but by then Hunt was only interested in the AFL.

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