Like the city itself, the nobles in the country around had been feudally subject to the Marquis of Tuscany. After Matilda's death they claimed to hold direct from the Empire; which meant in practice to be above all law. They exercised absolute jurisdiction over their serfs and dependants, and, when favoured by the situation of their castles, took toll, like the robber barons of Germany, of the goods which passed beneath their walls. Already they had proved to be thorns in the side of the industrious burghers; but at the beginning of the twelfth century their neighbourhood became intolerable, and for a couple of generations the chief political work of Florence was to bring them to reason. Those whose lands came up almost to the city gates were first dealt with, and then in a widening circle the country was cleared of the pest. Year after year, when the days were lengthening out in spring, the roughly organised city militia was mustered, war was declared against some specially obnoxious noble and his fortress was taken by surprise, or, failing that, was subjected to a siege. In the absence of a more definite grievance, it was enough to declare his castle dangerously near the city. These expeditions were led by the nobles who were already citizens, while the country neighbours of the victim looked on with indifference, or even helped to waste the lands or force the stronghold of a rival. The castle once taken, it was either levelled with the ground, or was restored to the owner on condition of his yielding service to the Republic. And, both by way of securing a hold upon an unwilling vassal and of adding a wealthy house and some strong arms to the Commonwealth, he was compelled, along with his family, to reside in Florence for a great part of every year.