"The Romans were more imaginative in the torments they imposed"
Torture was commonly used in Roman times to extract confessions and punish criminals, often as a prelude to execution. Torture was so normal that the confessions of accused slaves could only be accepted if they had been extracted by torture – slaves were not deemed honest enough to confess unless under extreme circumstances. The most famous Roman form of torture was also a method of execution: crucifixion. Other forms of punishment included flogging, crushing, stoning, hot coals, the breaking wheel, dismemberment, disembowelment, bull baiting, being thrown to wild animals, impalement, drowning, strangling, racking, untrained gladiatorial fights and burning at the stake.
A list of Christian martyrs and the punishments they underwent at the hands of the Romans can be found here.