This paper examines the late 1st millenium BC battle and battlefield of Allia near Rome from the perspective of the changing topography caused by the meandering Tiber river. It is argued that in the past scholars have paid too much attention to the current topography of the region where the battle of Allia is presumed to have been fought, and have not taken into account the fact that Tiber river - a dominating feature in the site - has changed its course several times over the centuries. Accordingly, also the ancient authors - who wrote centuries after the event - describing the battle may give faulty information as they too might have been mislead by the contemporary Tiber river valley topography of their time which may not have corresponded with that of the time of the battle
