In the early months of the Boer War of 1899-1902 Aliwal North was held by the Boers.
During the Boer War 1899-1902 he volunteered for service against the English and joined Gen.
On the outbreak of the Boer War in 1899, these same chiefs, at a great meeting held in the presence of the resident commissioner, gave a further protestation of their loyalty to Her Majesty.
His great work The American Commonwealth, which appeared in 1888, was the first in which the institutions of the United States had been thoroughly discussed from the point of view of a historian and a constitutional lawyer, and it at once became a classic. His Studies in History and Jurisprudence (1901) and Studies in Contemporary Biography (1903) were republications of essays, and in 1897, after a visit to South Africa, he published a volume of Impressions of that country, which had considerable weight in Liberal circles when the Boer War was being discussed.
In the Boer War of1899-1902Winburg was one of the Boer centres in the guerrilla fighting which followed the fall of Pretoria.