On succeeding to the English crown, however, he came over at once to take possession of the realm, and abode there for over a year, displaying the most restless energy in setting to rights the governance of the realm. He expelled all Stephen's mercenaries, took back into his hands the royal lands and castles which his predecessor had granted away, and destroyed hundreds of the "adulterine" castles which the barons and knights had built without leave during the years of the anarchy. Hardly a single magnate dared to oppose him--Bridgnorth, now a castle of the Mortimers, was the only place which he had to take by force. His next care was to restore the bureaucracy by which Henry I. had been wont to govern. He handed over the exchequer to Nigel, bishop of Ely, the nephew of the old justiciar Roger of Salisbury, and the heir of his traditions. His chancellor was a young clerk, Thomas Becket, who was recommended to him by archbishop Theobald as the most capable official in the realm. A short experience of his work convinced the king that his merits had not been exaggerated. He proved a zealous and capable minister, and such a strong exponent of the claims of the crown that no one could have foreseen the later developments by which he was to become their greatest enemy. The machine of government was beginning to work in a satisfactory fashion, and the realm was already settling down into order, when Henry was called abroad by a rebellion raised in Anjou by his brother Geoffrey--the first of the innumerable dynastic troubles abroad which continued throughout his reign to distract his attention from his duties as an English king. He did not return for fifteen months; but when he did reappear it was to complete the work which he had begun in 1155, to extort from the greater barons the last of the royal fortresses which still remained in their hands, and to restore the northern boundaries of the realm. Malcolm IV., the young king of Scotland, was compelled to give up the earldoms of Northumberland and Cumberland, which his father Henry had received from Stephen. He received instead only the earldom of Huntingdon, too far from the border to be a dangerous possession, to which he had a hereditary right as descending from Earl Waltheof. He did homage to the king of England, and actually followed him with a great retinue on his next continental expedition. In the same year (1157) Henry made an expedition into North Wales, and forced its prince Owen to become his vassal, not without some fighting, in which the English army received several sharp checks at the commencement of the campaign.