Demographic history of Scotland towns had populations of over 10,000, with the capital, Edinburgh, the largest with 57,000 inhabitants. The Highland and Lowland Clearances led to the depopulation of rural areas, but overall the population of Scotland grew rapidly in the late eighteenth and nineteenth centuries. By 1801 it had reached 1,608,420 and it grew to 2,889,000 in 1851 and 4,472,000 in 1901. By the beginning of the twentieth century, one in three lived in the four cities of Glasgow, Edinburgh, Dundee and Aberdeen. Glasgow emerged as the largest city, with a population of 762,000 by 1901, making it "the Second City of the
Hillforts in Scotland settlement developed in the Hownam model is still seen as having some validity. A. H. A. Hogg identified four types of hillfort: contour forts, promontory forts, cliff forts and ridge forts. Contour forts, where banks and ditches are moulded to the shape of the hill, are the dominant form in Scotland. Less significant are promontory forts, usually employing coastal features, such as the largest one in Scotland at the Mull of Galloway. Different types of defensive style occurred throughout the Iron Age period, some of which may have been a response to Roman siege warfare. There were different combinations in