Complex sentence: Julian's subordinate commanders were nervous, the Persian army featured cataphracts in the centre and the formidable clibanarii on the wings, in addition to these were elephants and masses of infantry to the rear.
Split into simpler sentences: Julian's subordinate commanders were nervous, as the Persian army featured cataphracts in the centre and the formidable "clibanarii" on the wings. There were also war elephants and masses of infantry to the rear.