Roman roads in Britannia were initially designed for military use, created by the Roman Army during the nearly four centuries (AD 43–410) that Britannia was a province of the Roman Empire. It is estimated that about 2,000 mi (3,200 km) of paved trunk roads (surfaced roads running between two towns or cities) were constructed and maintained throughout the province. Most of the known network was complete by 180. The primary function of the network was to allow rapid movement of troops and military supplies, but it subsequently provided vital infrastructure for commerce, trade and the transportation of goods.