Final answer:
Paul, who was a Roman citizen, was beheaded in Rome during Emperor Nero's reign. Beheading was a form of execution reserved for Roman citizens, as opposed to crucifixion, which was used for Jesus.
Step-by-step explanation:
The individual who was a Roman citizen and was beheaded rather than crucified was Paul. According to historical accounts, including Church tradition and scholars, Paul was martyred in Rome during the reign of Emperor Nero. This is in contrast to the crucifixion method typically used by the Romans, which was applied to Jesus, as he was seen as a rebel against the Roman social order and government. Execution by beheading was considered a privilege reserved for Roman citizens, which Paul was, making his martyrdom distinct from other forms of capital punishment used by the Romans at the time. Saint Peter, another leading figure in the early Christian church, was also martyred in Rome around the same time, but according to tradition, he was crucified.