Anglo-Saxon Institutions. 449-1066 33 Uncertain service was the characteristic of unfree tenure, and when this was commuted into burgage tenure by the lord of a semi-servile industrial group, it went far towards marking off that group from an ordinary manor, and started it towards the organisation and privileges of the older boroughs. As the boroughs grew in wealth through industry and trade, it became possible for their lords to get a greater income from them; and, as the royal boroughs were the most numerous, the king profited most. The imposition of various tolls was always the accompaniment of a flourishing market upon any lord's domains. As the business of the borough courts increased, the fines received from them by the king, as from the shire courts, increased. Thus a substantial revenue was furnished the king from his boroughs, consisting of rents, tolls, and fines. These items, taken together, were known as the firma burgi, and formed part of the ferm of the shire for which the sheriff was held responsible. The boroughs were not slow to recognise that they differed from the other communities, that they had special needs, and that, as population and wealth increased, so did their power to obtain privileges from their lords. To gain the right to pay the sheriff the firma burgi in the form of a fixed, lump sum, instead of running the chance of its increase and suffering the petty annoyance of having it dealt with in detail, was the first important step towards independence taken by the boroughs. To be able to deal with the sheriff solely at the gate became an ambition. But the story of the borough's strife for independence follows, rather than precedes, the Conquest. The facts to note here are that the boroughs had come to contain an important, middle-class population; that they had a form of government of their own, an increasing esprit de corps, and a knowledge of their own special needs. d. Anglo-Saxon Feudalism.—With the consideration of the boroughs, there has been completed a brief survey of the Anglo-Saxon local government as it existed in tlie