Aldie, Va., March 2, 1863. Detachment 1st Vermont Cavalry. About 50 or 60 men of Companies H and M formed the rear squadron of a Federal force of about 400, returning from Middleburg At Aldie, where a stop was made to water horses, the rear-guard was surprised by a detachment of Mosby's command, under the personal command of Mosby and both its captains, with 15 to 17 men, were captured. The 1st Vt. was included in the cavalry brigade of Col. Johnstone, who stated the Federal force to be 50, besides the 2 captains, the Confederate force about 70. Mosby gave the Federal strength as 59 besides the 2 captains and his own as only 17.
Source:: The Union Army A History of Military Affairs in the Loyal States 1861-65., Records of the Regiments in the Union Army., Cyclopedia of Battles., Memoirs of Commanders and Soldiers. 8 vols. Madison: Federal Publishing, 1908., vol. 5.
See also Benedict, ii:582