2For all that was mightiest among the nations of Gaul assembled and came in arms to Alesia, three hundred thousand strong; and the number of fighting men inside the city was not less than a hundred and seventy thousand. Thus Caesar, caught between so large hostile forces and besieged there, was compelled to build two walls for his protection, one looking towards the city, and the other towards those who had come up to relieve it; he felt that if the two forces should unite his cause was wholly lost.