Ancient Conquest's problem was it used hexes, and correspondingly low movement allowances. It could take centuries to go from Babylon to Memphis. I also felt its combat system better fitted a game with shorter turns, but as to its atmosphere it was a splendid thing. Rick, in response to your request, here is a description of Ancient Conquest. However, there are several major differences between Ancient Conquest and Britannia as well.
Victory is calculated in a unique way as well.
Each player can earn a maximum of 40 victory points, all of which are itemized on a separate sheet. Each color has the victory points broken down as to which of the individual nations need to perform a task, often with a time limit involved. There are no provisions for playing the game with more or less than four people. The map is printed on yellow paper, with blue ink for water, red ink for major cities and provincial names, and black ink for the remainder of terrain features, including, mountains, minor cities and desert, as well as the hexagonal borders dividing the terrain. Blue, red and yellow each have four separate nations, and green has five.