The ancient Romans had two classes of taxes: the tributa and the vectigalia. Tributa included the tributum soli (a land tax) and the tributum capitis (a poll tax). The vectigalia consisted of four kinds of tax: the portoria (poll tax), the vicesima hereditatium (inheritance tax), the vicesima liberatis (postage tax), and the centesima rerum venalium (auction sales tax). Cities may have occasionally levied other taxes; however, they were usually temporary. In ancient Rome there was no income tax, instead the primary tax was the portoria. This tax was imposed on goods exiting or entering the city. The size of the tax was based on the value of the item itself. It was higher on luxurious or expensive items, but lower on basic necessities. It was abolished in 60 BCE as it was no longer needed. The Roman empire's increasing size allowed for the government to procure sufficient funds from tributaries. Roman veterans were exempt from paying the portoria tax. Augustus created the vicesima hereditatium and the centesima. The vicesima was an inheritance tax and the centesima was a sales tax on auctions. Both policies were unpopular. They were designed to fund the aerarium militare, which was a service that provided money to veterans. Caligula abolished the centesima rerum venalium on account of its unpopularity. Caracalla granted Roman citizenship to all male residents of the empire, which was likely a method of increasing the taxable population of the empire. Under Constantine, it had become difficult to pay taxes due to the continued debasement of the solidus, increasing the prevalence of payment in kind.
