As late as August 29, 1862, the Union command did not know the size of the Confederate force south of Richmond and was uncertain whether it faced a full-scale invasion or only a cavalry raid. Colonel Leonidas Metcalfe rode out of Richmond with Union cavalry to gather information, and south of Kingston his men encountered Colonel John Scott's pickets. The Union cavalry attacked, and Scott's men offered little resistance before retreating south toward General Patrick Cleburne's infantry as the Federals pursued them down the Old State Road. Hoping to avenge his defeat by Scott at Big Hill on August 23, Metcalfe pressed forward, but instead of a small, demoralized cavalry force he found a brigade of Confederate infantry waiting. When the Union horsemen came within twenty-five paces, the Confederates opened fire, emptied several saddles, and halted the advance. The Federals then dismounted and renewed the attack, but they could not break the Confederate position, and Metcalfe finally ordered a withdrawal back to the Federal lines.