This word is used here to mark a break in the main story line as the author shifts to telling background information about Pilate's tradition of releasing a prisoner at feasts and about Barabbas. (See: [[rc://en/ta/man/translate/writing-background]])
# There with the rebels in prison ... in the rebellion, was a man named Barabbas
"At that time there was a man called Barabbas, who was in prison with some other men. They had committed murder when they rebelled against the Roman government"
This refers to Pilate releasing a prisoner at feasts. This can be made clear. AT: "to release a prisoner to them as he had done in the past" (See: [[rc://en/ta/man/translate/figs-explicit]])