In 1913, Maritz was offered a commission in the Active Citizen Force of the
Union Defence Force. He accepted and, after attending a training course, he was appointed to command the military area abutting
German South-West Africa. In August 1914, he was promoted to Lieutenant-Colonel. There is evidence that he started colluding with the Germans at a very early stage. As early as the (southern hemisphere) autumn of 1913 he had contact with the German governor in the neighbouring country. On 23 September 1914 Maritz was ordered to advance in the direction of the German border, to support the Union's invasion in the vicinity of
Sandfontein, where a portion of Lieutenant-Colonel Lukin's force was stranded. He refused to do so. Then he was ordered to relinquish command to another officer and return to Pretoria, but again refused to do so. On 9 October he eventually decided to rebel. The next day he occupied the town of
Keimoes. Then on 22 October he was wounded in a skirmish with government troops and he was taken to German South-West Africa. Some people have named the rebellion after him. ==Later life==