In Steven Saylor's Roma, The Novel of Ancient Rome we encounter several Fabii with the name Kaeso Fabius Dorso. While most are fictional, some where not (Smith, Dictionary of Greek and Roman Biography and Mythology, page 1069) – although they are listed by Smith as "C. Fabius Dorso" – and there was our Kaeso Fabius who stayed on the Capitol during the siege by the Gauls and performed sacred rites in the occupied section of the city, as reported by Dio Cassius – Fragments Book VII:
The Romans who were on the Capitol under siege had no hope of safety, unless through the aid of Heaven. For so
scrupulously did they observe the mandates of religion, although in
every extremity of evil, that when one of the sacred rites needed to be
performed by the pontifices in another part
of the city, Kaeso Fabius, who was then exercising the office of
priest, descended for the purpose from the Capitol after arraying
himself as was his wont, and passing through the enemy, performed the
customary ceremony and returned the same day.
6 I marvel at the barbarians, on the one hand, because, either on account of the gods or his bravery, they spared him; yet still more do I marvel at the man himself, for two reasons: first, that he dared to descend alone among the enemy, and again, that when he might have withdrawn to some place of safety, he refused, and instead voluntarily returned up to the Capitol again into manifest danger. For he understood that they hesitated to abandon the spot which was the only part of their country they still held, but saw at the same time that no matter how much they desired to escape it was impossible to do by reason of the multitude of the besiegers.
(Hat tip N.S. Gill)