Bethesda Softworks mother company ZeniMax has acquired Arkane Studios, adding to its stable of studios that already includes id Software.
Bethesda's Pete Hines made the announcement during the introduction to John Carmack's QuakeCon 2010 keynote. Terms were not disclosed.
"We are extremely pleased to join the family of Bethesda and id Software," Arkane founder Raphael Colantonio told the audience.
"I don't know how it could be better."
Hines came back on stage and said that Bethesda and Arkane were collaborating on an "unannounced project" but it would be "a while before we're talking about it".
Hines did say that we could expect to hear about it at a future QuakeCon.