Amongst the innovations introduced by the Normans, it may be read in the Saxon Chronicle how “they wrought castles throughout the land,” novelties to the people of the country, who seem to have retained much of that old Germanic aversion to castles which is traceable in the Frison law against building stone walls above a certain height; and accordingly from this time the Scots no longer swept the country in their invasions to the gates of Durham, but were stopped at Werk, Norham, and other feudal strongholds which they were obliged to invest, or if they advanced further into the country, to blockade. The royal castle was now attached to the royal burgh, and its garrison provided by the knights who held their lands by the tenure of castle-guard; the neighbouring gentry probably, differing little from the thegns who in earlier times had been bound to keep the burgh in repair. The name of Burgher henceforth undoubtedly belonged only to the actual possessors of property within the walls, the bulk of whom had probably from the earliest period of their location within burgh formed the commercial part--the Twyhyndmen, as the Upland thegns were the Twelfhyndmen--of the community. It was the Anglo-Norman Burgh, with its feudal castle, and its civic population distinct and separate from the garrison, which was the model of the burghs established, or confirmed, by David beyond the Tweed. It may be doubted whether any free communities engaged in commerce, and occupying walled towns, were in existence much before this reign even in the Lothians, though the germs of such societies may have existed at Scone, Edinburgh, Stirling, and other places, which were of a certain importance at that early period. Had there been burghs or walled towns in any part of Saxon Northumbria before the close of the eleventh century, the invading Scots would have surely been checked before they reached the gates of Durham; the unopposed incursion of the Second Constantine as far as the Tees marking apparently the non-existence, in that quarter, of any walled town in the middle of the tenth century, capable of arresting the progress of a hostile force. As the sees of Glasgow and St. Andrews may be regarded as the models left by David for the regulation of the other Scottish bishoprics, so the _Hanse_ or community of the Four Burghs of Roxburgh, Berwick, Edinburgh, and Stirling, was the leading commercial association of the same reign, all other burghs as they grew into existence conforming to its rules and ordinances; and as the _Hanse_ was composed of four burghs, so each Burgh seems to have been originally divided into four Wards--in strict accordance with the theory which divided in a similar way the great rural association of the shire into four quarters. Over every Ward was placed a Bailie, a type of the rural “Mair of the Quarter,” and sometimes known, like the President of the Frison Quarter, as the _Ferthyngman_; the