British settlers in the Transvaal were now treated worse than before. Negotiations were carried on between the British government and the Boers, but were suddenly broken off by the latter, who demanded that no more British soldiers should be sent to South Africa. This demand being refused, the Boers, supported by their brethren of the Orange Free State, declared war against Britain, and invaded Natal and Cape Colony in October 1899. Ladysmith, in the north of Natal, was invested by the Boers, the British army there being under the command of General Sir George White. The Boers also besieged Kimberley, an important town, containing valuable diamond-mines, in the north-west of Cape Colony. Farther north a small British garrison was hemmed in at Mafeking, a little town near the Transvaal border. Lord Methuen, with a British column, was sent to the relief of Kimberley, and Sir Redvers Buller, with a strong army, set out to relieve Ladysmith; but both these generals sustained reverses, the former at Magersfontein, and the latter at the Tugela River. Towards the end of December, Lord Roberts, with Lord Kitchener as chief of his staff, was sent out to the Cape as Commander-in-Chief. On the 15th of February, Kimberley was relieved; and shortly afterwards the Boer general Cronje, with his entire army of upwards of four thousand men, surrendered to Lord Roberts at Paardeberg. After several gallant attempts, General Buller finally succeeded in relieving Ladysmith, which had been besieged by the Boers for four mouths. Bloemfontein, the capital of the Free State, was next captured by Lord Roberts; and on the 17th of May, Mafeking was relieved. The brave little garrison of this town, under their able and dauntless leader, Baden-Powell, had endured the greatest privations, and during a siege of seven months had maintained the most marvellously gallant defence of modern times. Before the end of May, Johannesburg surrendered to Lord Roberts; and on the 5th of June he hoisted the British flag in Pretoria, the capital of the Transvaal. About the same time the Orange Free State was annexed to Great Britain under the name of the Orange River Colony; and on the 1st of September the Transvaal was declared British territory. The most striking feature of this war was the loyalty and enthusiasm displayed by the colonies in the cause of the mother-country. Canada, Australia, and New Zealand vied with each other in sending volunteers to fight for and uphold the rights of their fellow-colonists in South Africa, thus giving to the world such an evidence of the unity of the British Empire as it had never before seen. Volunteers from the mother-country, too, rallied round their nation's flag in great numbers, and nobly went forth to maintain her cause on the field of battle.