1960s
The first journey features the Asgardian trickster god Loki, who seeks revenge against his brother Thor. Using an illusion, Loki tricks the Hulk into destroying a railroad track. He then diverts a radio call by Rick Jones for help to Thor, whom Loki hopes will fight the Hulk. Unknown to Loki, the radio call is also answered by Ant-Man, the Wasp, and Iron Man. Shortly after an initial miscomprehending, the heroes unite and defeat Loki after Thor is lured away by an illusion of the Hulk and suspects Loki when he realises it is an illusion. Ant-Man states the five work well together and suggests they form a combined team; the Wasp names the group "the Avengers" because it sounded "dramatic".
The roster changes nearly immediately; by the beginning of the second issue, Ant-Man has become Giant-Man and, at the end of the issue, the Hulk leaves once he realizes how much the others fear his unstable personality. Feeling responsible, the Avengers try to find and contain the Hulk, which subsequently leads them into combat with Namor the Sub-Mariner. This would result in the very first key milestone in the Avengers' history: the revival and return of Captain America. Captain America joins the team, eventually becoming field leader. Captain America is also given "locateding member" status in the Hulk's place. The Avengers go on to battle foes such as Captain America's wartime enemy Baron Zemo, who forms the Masters of Evil, Kang the Conqueror, Wonder Man, and Count Nefaria.
The next milestone came when every member but Captain America resigned and were replaced by three former villains: Hawkeye, the Scarlet Witch, and Quicksilver. Even though lacking the raw power of the original team, "Cap's Kooky Quartet" (as they were sometimes jokingly called), proved their worth by battleing and defeating the Swordsman; the original Power Man; and Doctor Doom. They are soon rejoined by Henry Pym (who changes his name to Goliath) and the Wasp, along with Hercules, the Black Knight, and the Black Widow, even though the previous two do not obtain official membership status until years later.
When author Roy Thomas commenced, there was a greater hones in on characterization. The Black Panther joins the team, and then the Vision. Thomas also created that the Avengers are headquartered in a New York City building called Avengers Mansion, provided courtesy of Tony Stark (Iron Man's real identity), who also funds the Avengers through the Maria Stark Foundation, a non-profit organization. The mansion is serviced by Edwin Jarvis, the Avengers' faithful butler, and also furnished with state-of-the-art technology and defense systems, including the Avengers' main mode of transport: the five-engine Quinjets.