This treaty being made, Robert returned to his dukedom, and gave himself over to his natural indolence and dissipation. Uncured by his misfortunes of a loose generosity that flowed indiscriminately on all, he mortgaged every branch of his revenue, and almost his whole domain. His barons, despising his indigence, and secure in the benignity of his temper, began to assume the unhappy privilege of sovereigns. They made war on each other at pleasure, and, pursuing their hostilities with the most scandalous license, they reduced that fine country to a deplorable condition. In vain did the people, ruined by the tyranny and divisions of the great, apply to Robert for protection: neither from his circumstances nor his character was he able to afford them any effectual relief; whilst Henry, who by his bribes and artifices kept alive the disorder of which he complained and profited, formed a party in Normandy to call him over, and to put the dukedom under his protection. Accordingly, he prepared a considerable force for the expedition, and taxed his own subjects, arbitrarily, and without mercy, for the relief he pretended to afford those of his brother. His preparations roused Robert from his indolence, and united likewise the greater part of his barons to his cause, unwilling to change a master whose only fault was his indulgence of them for the severe vigilance of Henry. The King of France espoused the same side; and even in England some emotions were excited in favor of the Duke by indignation for the wrongs he had suffered and those he was going to suffer. Henry was alarmed, but did not renounce his design. He was to the last degree jealous of his prerogative; but knowing what immense resources kings may have in popularity, he called on this occasion a great council of his barons and prelates, and there, by his arts and his eloquence, in both which he was powerful, he persuaded the assembly to a hearty declaration in his favor, and to a large supply. Thus secured at home, he lost no time to pass over to the continent, and to bring the Norman army to a speedy engagement. They fought under the walls of Tinchebrai, where the bravery and military genius of Robert, never more conspicuous than on that day, were borne down by the superior fortune and numbers of his ambitious brother. He was made prisoner; and notwithstanding all the tender pleas of their common blood, in spite of his virtues, and even of his misfortunes, which pleaded so strongly for mercy, the rigid conqueror held him in various prisons until his death, which did not happen until after a rigorous confinement of eighteen, some say twenty-seven, years. This was the end of a prince born with a thousand excellent qualities, which served no other purpose than to confirm, from the example of his misfortunes, that a facility of disposition and a weak beneficence are the greatest vices that can enter into the composition of a monarch, equally ruinous to himself and to his subjects.