From until 1709 the coinage of Scotland was unique, and minted locally. A wide variety of coins, such as the plack, bodle, bawbee, dollar and ryal were produced over that time. For trading purposes coins of Northumbria and various other places had been used before that time; and since 1709 those of the Kingdom of Great Britain, and then of the UK. Ancient history and Roman trade (–400) The earliest coins in Scotland were introduced by the Roman provinces of Britain that were obtained from trade with the westernmost outpost of the Roman Empire. Far from being isolated, the Celts of Caledonia, north of Hadrian's Wall, developed trade to the general benefit of the population, to the north of the Wall. Roman coins appear over a wide range across the country, especially sites near the Antonine Wall. Hadrian's Wall was also regarded as a means to regulate social traffic and trade north, rather than a military defence against the free northern tribes of the Caledoni. Civil settlements arose along south of the wall with shops and taverns that facilitated trade between the Empire and free north. It is possible to recognise groupings of coins from certain periods, during the Flavian and Antonine occupations; such as Cardean Fort Angus where Roman dupondius coins AD 69–79 date to the reign of Emperor Vespasian. Other sites include coins from North Uist dating to the 4th century until recently was thought to be beyond the sphere of known trade routes. Other native sites include the Fairy Knowe broch Buchlyvie, and the broch and dun at Gargunnock in Stirlingshire. Some sites include substantial silver treasure hoards most likely buried or abandoned in either Roman or native pots. Indicating the Roman governor of Britain paid large sums of money to the inhabitants of southern Scotland and possibly bribing the northern Caledonians to maintain peaceful relations with Romans and the British. Payments to chieftains are recorded in four areas; Edinburgh, Fife, Aberdeen and the Moray Firth. This may indicate such discoveries (e.g. the Birnie hoard of between 200–400 silver coins) were deposited as votive offerings. Examples including coinage of Constantine II (337–342) with over 20 such hoards found throughout Scotland. Rare examples include a base silver (potin) coin of Ptolemy XIII of Egypt, 80–51 BC In 410, trade ceased as the Roman Empire withdrew from the island of Albion. Early medieval period (500–900) As the Roman Empire