https://en.wikipedia.org/wiki/Tampa_2
The aforementioned Bud Carson later took the two-deep-safeties concept to the New York Jets in 1985. That year, the Jets made the playoffs as an 11-5 wild card. Carson's team split with the Miami Dolphins and prime Dan Marino that season. The first time Marino faced Carson's defense, he passed for 136 yards, no TDs, and a pick. During the return match against the Jets, Marino forced the downfield game to eke out a 21-17 win -- 3 TD passes but also 3 INTs.
As the NFL is a copy-cat league, the strategy spread. Two-deep safeties gave defenses a strong chance against the elite passing games like Miami, San Diego, and Green Bay (remember Lofton & Jefferson together?). Fans who remember the 1980s NFL will remember that none of those high-flying downfield passing squads would win a title -- "defense wins championships" became the conventional wisdom.