The labour of leading the House of Commons was in itself heavy, and after Lord Sidmouth's retirement from office in 1821 he also undertook the duty of superintending the home office, as he had done for Lord Liverpool early in 1809. Throughout June and July of 1822 his mind was visibly overwrought, and he suffered also acutely from gout. His usually neat handwriting was hardly legible; he forgot appointments. It was remarked in the House of Commons that he denied all knowledge of a document which was actually lying before him. On 9 Aug. he had an audience of the king, at which the king was so struck with his manner that he recommended him to consult a physician. Later in the same day the Duke of Wellington thought his case so serious that he wrote privately to Dr. Charles Bankhead [see under Bankhead, John], Lord Londonderry's physician, warning him to take precautions (Gleig, Life of Wellington, iii. 118). Dr. Bankhead was summoned to St. James's Square, and advised Lord Londonderry to go down to his country seat, North Cray Place, Kent, and there, having caused his razors to be removed, he remained in attendance. Lord Londonderry's mind continued affected, and on 12 Aug. he cut his throat with a penknife in his dressing-room, and died almost immediately. His death profoundly affected the public. After the inquest, at which a verdict of unsound mind was returned, his body was buried in Westminster Abbey on 20 Aug. between the graves of Pitt and Fox. There were some scandalous demonstrations when the hearse reached the abbey doors, but in the main the expression of public grief was unanimous. He had no children, and was succeeded in the title by his half-brother, Charles William, lord Stewart. His widow died on 12 Feb. 1829, and eight days later was buried beside her husband in Westminster Abbey.
Few men have taken part in so many important events as did Lord Castlereagh in the quarter of a century that covers his public career; few men have been the victims of such constant and intense unpopularity. Yet the services which he rendered to his country and to Europe were signal. He bore a large part, and often the principal part, in crushing the Irish rebellion of 1798, in effecting the parliamentary union of Great Britain and Ireland, in initiating and in continuing the war in the Peninsula, in combining the great powers of Europe against Napoleon, and in resettling the affairs of Europe at Vienna. In manner he was cold; ‘as for my friend Lord Castlereagh,’ writes Lord Cornwallis, ‘he is so cold that nothing can warm him’ (Correspondence, iii. 506). This made him many social enemies, especially in Dublin in 1800, and to the end of his life it was a characteristic trait. ‘Just and passionless’ was Caulaincourt's description of him. He came in turn into collision with almost every party; he had his own way almost always, and was rewarded by being equally feared and hated. He was in collision with the Irish patriots on the union, with the Irish protestants on emancipation, with the whigs on the continuance of the war, with the radicals on popular rights and repressions, with the French legitimists when he was prepared to negotiate with Napoleon in 1814 without first pressing for his abdication, with the Holy Alliance at the time of the congress of Troppau. Even the English tory party looked somewhat askance on a statesman who was not an Englishman himself and was a self-made man. In domestic affairs it must be owned that Castlereagh's repressive system was outworn, and that many of the measures which he supported if he did not originate them, whatever might be said of them in the crisis of the war, were unjustifiable in time of peace. But there must be set to his credit his general comprehension of the strategic principles on which alone Napoleon could be combated, the knowledge of character and of war shown in his selection of Wellington for the Peninsular command, and his steady support of him in Portugal, and the moderation and wise disinterestedness, when, as almost the arbiter of Europe in 1815, he brought about a fairly durable settlement, and at least averted further war. He was no orator, though the stress of circumstances during the debates of 1798 and 1800 made him a fair speaker and a ready debater. His speeches were long, and he had a tendency to be tedious and confused, to mix metaphors, and to fall into indiscreet phrases, such as his well-known ‘ignorant impatience of taxation’ uttered in 1816; yet he ‘never spoke ill,’ was sensible and well informed, and could not be daunted or put down. In person he was tall and handsome, and was much admired; his manners were exquisitely and unfailingly courteous; his dress, like his personal bearing, was plain and simple. He spoke French slowly but correctly, and in dealing with kings and ministers possessed an invaluable combination of courtier-like suavity and invincible resolution. Constantly it happened that his strong will and unflinching courage dominated the cabinet (Lord Aberdeen to Bishop Wilberforce, Life of S. Wilberforce, ed. 1888, p. 236), and as he