In the Roman Empire, the following people could become citizens:

• People who were from the Latin states were granted citizenship.
• The children of slaves who were freed became citizens.
• Foreigners who lived in conquered lands were given partial citizenship.
• Children born to a legionary were, however, denied citizenship unless the legionary married after his release from service.
• Some individuals received citizenship because of their outstanding service to the empire.
• One could also buy citizenship, but at a very high price.

Rights given:

• The right to vote in the Republic, except for women.
• The right to make contracts
• The right to have a legal marriage
• The right to have a trial (to appear before a proper court and to defend oneself)
• Citizens couldn't be sentenced to death unless they were accused of treason.
• Even if sentenced to death no roman citizen could be sentenced to die at the cross. (St. Paul was beheaded (he had been born a jew, in Anatolia but was a roman citizen. St. Peter on the other hand was cruzified)
• Citizens couldn´t be submited to torture

After AD 212, all freemen in the Empire were granted citizenship from the Constitutio Antoniniana.

All these rights were (as everywhere down the ages) sometimes ignored.

• Roman citizenship