Named after the sword of Arthurian legend, the Excalibur team of superheroes was formed by Captain Britain to continue the X-Men's legacy after their apparent demise at the hands of the Adversary.
Their base was at Captain Britain's lighthouse, on the shores of the UK, but also at a nexus of alternative realities. Many of their battles have been fought across alternate worlds.
The first Excalibur team consisted of Captain Britain, his lover Meggan (a shapeshifter) and several one-time members of the X-Men / related mutant teams.
The team disbanded after Captain Britain and Meggan married and was reformed by Captain Britain twice with new lineups.< LESS