In the meantime, in late 1611, prince Dmitry Pozharsky was asked to lead the public opposition against the Poles, organized by the merchants' guild of Nizhny Novgorod. The respected town butcher (literally, a meat-trader) Kuzma Minin oversaw the handling of funds donated by the merchants to form the Second Volunteer Army (). When part of the Polish army mutinied in January 1612 due to unpaid wages and retreated from Russia towards the Commonwealth, the forces of the Second Volunteer Army strengthened the other anti-Polish Russian forces in Moscow. The 9,000-strong Polish army under hetman Jan Karol Chodkiewicz attempted to lift the siege and clashed with Russian forces, attempting to break through to Polish forces in the Kremlin on 1 September. The Polish forces used cavalry attacks in the open field, exercising tactics that were new to them: escorting a mobile tabor fortress through the city. After early Polish successes, the Russian Cossack reinforcements had forced Chodkiewicz's forces to retreat from Moscow.