The Roman History · Amm. 24.2.17

But the account given by the old writers may serve to defend this modern attempt; for Æmilianus approached a gate protected by a stone-covered testudo, under which he safely forced his way into the city while the garrison was occupied in demolishing this stone roof. But Julian attacked a place completely exposed, while the whole face of heaven was darkened by the fragments of rock and weapons which were showered upon him, and was even then with great difficulty repulsed and forced to retire.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
Passage preview. Read in context for the complete text, notes and references.