After the Battle of Liaoyang in late August, the northern Russian force that might have been able to relieve Port Arthur retreated to Mukden (Shenyang). Major General Anatoly Stessel, commander of the Port Arthur garrison, believed that the purpose of defending the city was lost after the fleet had been destroyed. In general, the Russian defenders were suffering disproportionate casualties each time the Japanese attacked. In particular, several large underground mines were exploded in late December, resulting in the costly capture of a few more pieces of the defensive line. Stessel, therefore, decided to surrender to the surprised Japanese generals on 2 January 1905. He made his decision without consulting either the other military staff present, or the Tsar and military command, all of whom disagreed with the decision. Stessel was convicted by a court-martial in 1908 and sentenced to death on account of an incompetent defense and for disobeying orders. He was later pardoned.