sentences:  Wolchefit was defended by a garrison of about 4,000 men under Colonel Mario Gonella.The stronghold had been besieged by irregular Ethiopian forces, led by British Major Ringrose, since May 1941; the besieging force was later augmented by the arrival of units from the British Indian Army and part of the 12th African Division.Several attacks and counterattacks were launched between May and August 1941.