Battle of Orsha
According to "Rerum Moscoviticarum Commentarii" by Sigismund von Herberstein , the primary source for information on the battle , the much smaller army of Lithuania-Poland ( under 30 , 000 men ) defeated a force of 80 , 000 Muscovite soldiers , capturing their camp and commander . 
<triplet> Rerum Moscoviticarum Commentarii <subj> Sigismund von Herberstein <obj> author