Yes it is and they are all about the same from the start. After 1404/DOD they did change them. 1404/DOD did give a lot more vs the rest. There is even a really good Mod for 1404/DOD.
So like dmdilks said, Dawn of Discovery was the title of the Anno series in North America, first adopted with Anno 1404 i think. I couldn't find a source as to why, but it's the same game, just a different name.