Petrus Johannes Liebenberg

Liebenberg was ordered by general Piet Cronjé to invade the Cape Colony both to sabotage the railway Cape Town-De Aar-Bloemfontein-Pretoria near De Aar, which was vital for the invading British army of Lord Roberts, and to recruit Boer men in the British Cape Colony (Afrikaans: "nuwe burgers", new citizens, as "Cape rebels") to the cause of the two Boer Republics at war.[3] He left Cronjé's army camp (laer) at Magersfontein at the end of January 1900 with some 200 men and two cannon. He was later joined by Commanders Koos Jooste and Andries de Wet, who had obtained permission from Transvaal president Paul Kruger for their plan to destroy the railway near De Aar.[2][4][5]

Cape rebel Lucas Petrus Steenkamp (1845–1919)[6] became the Assistant Chief Commander under general Liebenberg.[7] Steenkamp had considered the recruitment of up to 6000 soldiers in the Cape Colony as the priority, before going south and cutting the railway and British lifeline between De Aar and Hopetown.[8] On 15 February 1900, they occupied Prieska and environs in the Karoo, Northern Cape and declared it a part of the Orange Free State.[2][9] Two days later, Cronjé sent an urgent message to now speedily attack the railway.[10] Liebenberg recruited 200 men in Griekwastad on 28 February 1900 and chased away 500–700 British troops under Colonel Adye at the farm Houwater, some 40 kilometers north-west of Britstown.[11]

However, Liebenberg received an erroneous order by his superior general Jacob Johannes Marthinus Breytenbach (around 1860–1901)[12] to retreat from the Cape Colony, which he obeyed: as a result Prieska was recaptured by the British on 19 March 1900 and the Cape rebels were deserted by the invaders.[13] Subsequently, Orange Free State president Marthinus Steyn fired Breytenbach on 31 March 1900.[14] Nothing had come of the plan to destroy the railway near De Aar to help break the encirclement of Cronjé by Lord Roberts at Paardeberg.

After the British occupation of Bloemfontein on 13 March 1900, the capital of Orange Free State, Liebenberg returned to Griqualand West and established his headquarters at Rooidam. General S. P. Du Toit reported on 12 April 1900 that Liebenberg was acting general for Griqualand West.[15] In April 1900 Liebenberg was reinforced in North West Cape by the Krugersdorp Commando from Natal.[16] British general Archibald Hunter forced him to retreat to the North in May 1900.[2]

In May 1900 Liebenberg advanced from Veertien Strome (Warrenton) with at first 300, but finally with 450 men to block 1149 British troops of Colonel B.T. Mahon, who came from Barkly West to relieve the besieged town of Mafeking.[17] Liebenberg's force was composed of the Commandos from Bloemhof and Vryburg, reinforced by Louis Botha from Mafeking and others. He occupied a strong position on the ridge at the south bank of the Molopo River near Mafeking, while Boer burgers from Rustenburg en Marico protected the ridge on the north bank waiting for the unsuspecting troops of Mahon to pass in between. This plan was supervised by supreme general Koos de la Rey, who arrived at Mafeking on 14 May 1900.[18] However, two horses on the north bank of the Molopo bolted under British cannon fire, leading the Rustenburg and Marico burgers there to retreat in a hurry. In the following night they left a gap between them through which Mahon could slip through. He and his troops entered Mafeking in the early hours of 17 May 1900 ending the 217-day siege.[19]

After the Fall of Pretoria on 5 June 1900 Liebenberg was present at the meeting on the same day of more than 30 Boer commanders in the whiskey distillery of Lewis & Marks at Pienaarspoort, east of Pretoria. They decided to continue their struggle and defend the mountain ridge from Wonderboomspoort to Donkerhoek east of Pretoria.[20] Liebenberg participated with his Griqualand troops in the lost Battle of Diamond Hill (Slag van Donkerhoek), where Louis Botha ordered a retreat to Bronkhorstspruit on 12 June 1900.[2][21]

When president Kruger requested general De la Rey to start another invasion of the Cape Colony, he acquiesced on 2 July 1900 and would be accompanied by the generals Liebenberg, Du Toit, Snyman and Douthwaite for their strong resistance at Donkerhoek.[22] Enthused by the Boer victory at Silikaatsnek (Silkaatsnek) near Hartbeespoort west of Pretoria on 11 July 1900 after months of defeats, Boer volunteers enlisted from West Transvaal. General De la Rey sent Liebenberg with a Krupp cannon and a pom-pom to command the Potchefstroom Commando on 14 July 1900.[2][23]

Generals Christiaan De Wet and Liebenberg combined their forces to a total of 1500 men and laid a siege around Frederikstad on 20 October 1900 but had to flee after five days when British reinforcements under Lt.-Col. H. T. Hicks arrived.[24]