The Avengers are a household name because of the MCU, but it wasn't always that way. The Avengers burst onto the scene in 1963, combining Marvel's greatest heroes and pitting them against threats that no one hero could face on their own. Avengers was long the place for Marvel fans to read about their favorite heroes in one place, taking on big stakes threats that made comics exciting. The Avengers' popularity fell down a well once the X-Men became ascendant in the 1980s, only coming back in the '00s because Marvel toned down on the X-Men hype.
Source：https://www.cbr.com/marvel-avengers-comics-important-history-trivia/
