Following the early death of Svetoslav's son, Georgi Terter II, Tsar Mihail Shishman took over. He spent the years of his rule, from 1323 to 1330, almost entirely on horseback, the peaceful years under Todor Svetoslav a thing of the past. The Despot of Vidin Mihail Shishman was elected Tsar by the boyars. His enthroning marked the beginning of a new dynasty, the Shishmans, which was to hold power until the decline of the Second Bulgarian State. Mihail Shishman fought many battles, knew the joy of victory and the frustration of defeat. His first battles with the Byzantines in Thrace showed the basileus the strength and experience of his opponent. Constantinople acknowledged Bulgaria's gains south of the Balkan range. Despot Voisil who was holding several fortresses in the Sub-Balkan valley was subdued, too.
Several years later the hostilities between Bulgaria and Byzantium were reopened and Mihail Shishman was forced to turn to an old ally and a still older enemy, the Tartars, for help. The Bulgarian raids in Thrace, in the region of Adrianople, harassed the empire, which was at that time torn by internal struggles. However, it seemed Mihail Shishman was unable to hold the seized territories and he proposed peace. The 1324 treaty was sealed by Mihail Shishman's marriage to the sister of the young Emperor Andronicus, Teodora, the widow of Tsar Todor Svetoslav Thus peace was secured from the south and the new dynasty was formally recognized. Later Mihail Shishman became involved in the internecine struggles with the secret hope of conquering Constantinople. However, he proved to be a poor diplomat. After an unsuccessful campaign in Thrace he worked to restore peace and the alliance with the emperor.
Peace with Byzantium was vital because of Bulgaria's strained relations with Serbia. It already controlled the larger part of Macedonia, and King Stefan Decanski was preparing for a war against Bulgaria. The Bulgarians accepted the challenge and the army headed for Velbuzhd (today's Kyustendil), expecting the allied Byzantine army to arrive.
However, dramatic events followed with grave consequences for Bulgaria. At the end of July 1330, after clashes between the two armies, their commanders agreed upon a truce. But the Serbian army violated the truce and launched a surprise attack which caught the Bulgarian army off-guard. The Byzantine army never showed up. The Serbian king fought fiercely, seeking vengeance for his sister Anna-Neda, the estranged first wife of the Bulgarian tsar. Mihail Shishman fought valiantly and died in the battle.