In mid-July 1803, Karađorđe obtained arms and munitions from Habsburg Serb merchants in Zemun. Later that month, he dispatched couriers through Šumadija calling for a meeting of Serbian notables to devise a strategy for resisting the Dahis. The flow of arms from the Austrian Empire into the Pashalik, combined with their inability to crush the guerrillas in the countryside, made the Dahi leadership increasingly uneasy. In January and February 1804, the Dahis launched a pre-emptive assault against the Pashalik's Serbian chieftains (known as "knezovi", or "princes"), killing between 70 and 150 of them. The killings outraged the Serbian "rayah", the Pashalik's tax-paying lower class. By this time, Karađorđe was a well known and well respected figure in Šumadija. He narrowly escaped being killed in the two-month massacre, which came to be known as the Slaughter of the Knezes (). Upon killing the chieftains, the Dahis impaled their severed heads on wooden stakes and put them on public display. On Candlemas, , the surviving chieftains assembled in the village of Orašac, near Aranđelovac, to decide on a course of action. They agreed to launch a rebellion against the Dahis and Karađorđe was elected without opposition to lead it. It is said that he twice refused to lead the uprising, arguing that his violent temper would make him unsuitable for the role. Karađorđe's initial refusal only reinforced the chieftains' convictions that he was the only suitable candidate, and eventually, he agreed to lead the rebels. This event marked the beginning of the First Serbian Uprising, the opening phase of what would come to be known as the Serbian Revolution.