After Byzantine troops conquered Bulgaria in 1018, Basil II wisely decided not to change the Bulgarian taxation system in order to placate the population.

Under the rule of Emperor Romanos III the population was forced to pay its taxes in coin rather than in goods-in-kind, which caused poverty and widespread unrest.

In 1040, Petar Delyan, who claimed to be a descendant of Samuil of Bulgaria escaped from Constantinople and began roaming throughout the Bulgarian lands, eventually reaching Morava and Belgrade.

[3] In the same time local Bulgarians from the Dyrrhachium area gathered around the soldier Tihomir[4] and headed westwards to reach the old capitals.

[6]Krum's campaigns Simeon I's campaigns Sviatoslav's invasion of Bulgaria Byzantine conquest of Bulgaria Uprising of Peter Delyan Second Bulgarian Empire With his enlarged army Petar II advanced to the south, surprised and defeated the Byzantine Emperor Michael IV the Paphlagonian at Thessaloniki.

[9] After the victory the Bulgarian troops under the voivoda Kavkan captured Dyrrachium on the Adriatic Sea and some forces penetrated deep into Thessaly eventually reaching Corinth, Epirus and most of Macedonia were conquered.

Another Bulgarian army led by Antim marched deep to the south and defeated the Byzantine commander Alakaseus in the battle of Thebes in Boeotia.

Upon the news of the Bulgarian success the Byzantine population of Athens and Piraeus who were uneasy due to the heavy taxes also revolted but were quickly crushed by Norman mercenaries.

Soon the Byzantines eliminated the resistance of Delyan's remaining voivodes, Botko around Sofia and Manuil Ivats in Prilep, thus ending the Bulgarian revolt.