There is a phrase "Ab Urbe condita"/"Anno Urbis conditae". It seems to me that there is no other game with this name. Developers could appropriate it while it's free.
There is also an interesting phrase - "Saeculum Novum", which means "New Age". But I think it's better for the next part. In addition, the developer could use the silhouette of a Roman Republican coin as a logo, and in the second part of the game (Anno Urbis conditae: Saeculum Novum) - a Roman Imperial coin. This option seems perfect to me from the point of view of a free license.