C. Marius recidendorum impedimentorum gratia, quibus maxime exercitus agmen oneratur, vasa et cibaria militis in fasciculos aptata furcis imposuit, sub quibus et habile onus et facilis requies esset; unde et proverbium tractum est “muli Mariani”.
(Frontinus, Strat. 4.1.7)
For the purpose of limiting the number of pack animals, by which the march of the army was especially hampered, Gaius Marius had his soldiers fasten their utensils and food up in bundles and hang these on forked poles, to make the burden easy and to facilitate rest; whence the expression “Marius’s mules.” (tr. Charles E. Bennett)
Crambe Repetita 