User blog comment:Master Sima Yi/AC: Brotherhood - Inventions of Leonardo da Vinci/@comment-3058930-20101002222016

Look I know some people are angry that in Brotherhood there is a tank and it is historically inaccurate, but not everything in a Assassin's Creed is true to history, like Robert De Sable died in 1193 not 1191, Jacopo De Pazzi fate in the game completely differed for real life. And it has be explained that the Templars have sometimes covered things up in history. So the Templars may of done the same with the tank, and the machine was being the developed in secret.