Peter Deljan sent friendly letters to his fellow Bulgarian rebel, Tichomir, inviting him to joint rule. But when the two men's armies were united, Deljan assembled them all and made a speech, saying that the country could never prosper with dual rule and they must choose between himself (a kinsman of tsar Samuel) and Tichomir. They proclaimed Deljan and Tichomir they stoned to death. Peter sent troops to capture the fort of Basilis and advanced on Thessalonike to face Michael IV