Bertram Chandler wrote two interstellar series – one featuring a Galactic Empire ruled by a series of non-hereditary Empresses while the other has a Republican Galactic Federation. Chandler's Empire and Federation, both relatively benign, have much in common – both covering the same volume of space, having much the same kind of Space Navy and both having the same commercial spaceflight company called "The Dog Star Line", suggesting that these are two alternate history timelines which branched off from the same original space travelling culture.