The Revolution broke out at the same time in east-central Greece as in the Peloponnese, that is, in the last ten days of March. This was a region with a deep tradition of armatolism. Especially in mountainous regions, wealthy armatole families with strong regional agents, protection and solidarity networks based on kinship relations and a considerable number of armed men well-prepared for war took action. All these made them powerful agents in regional society and led them to act independently and sometimes competitively toward the communal power, the prokritoi (local notables). In fact, the hesitance and sometimes the opposition of the local notables to the declaration of the Revolution gave many chieftains the opportunity to take advantage of the situation and impose their own regional rule. The region of Salona (Amfissa) was taken by the elderly Panourgias, just as Athanasios Diakos took Livadeia and Kontogiannis Patratziki (Ypati). They were assisted by other armed men such as Giannis Gouras, Andritsos Saphakas, Skaltsodimos and Bousgos. At the same time, Galaxidi, a naval centre in the Corinthian Gulf, revolted and soon the inhabitants of Athens began the siege of the Acropolis in which the Ottoman force was garrisoned. Attempts to occupy forts were made in Euboea as well. Finally, it is worth mentioning the return of Odysseas Androutsos from the Ionian Islands where he had found refuge in 1818. Androutsos was in the past the most powerful armatole of east-central Greece who inspired both admiration and fear amongst Christians and Muslims.

In the middle of April the first wave of repression against the insurgents in the Peloponnese was sent by Chursid, the pasha of the Peloponnese who was marching out against Ali Pasha of Ioannina. The plan of Omer Vryoni, who was actually the leader of the expedition, was to stifle the revolt in east-central Greece and by crossing the Isthmus to pass on to the Peloponnese. Indeed, Patratziki was abandoned by the revolutionaries while the Battle of Alamana on 23 April was destructive despite the sturdy resistance of Athanasios Diakos who was captured and met a violent death. A second revolutionary effort in the region of Gravia was more effective. There, at the beginning of May, Androutsos inflicted severe losses on the army of Omer Vryoni, thus confirming his reputation and domination of the chieftains of east-central Greece. A few days later, Gouras repeated the operation in the region of Giona, obliging the Ottomans to abandon their plans of reaching the Peloponnese. The most important battle took place at Vasilika at the end of August when Gouras and Dyovouniotis confronted the army of Beyran Pasha. The latter had repressed the revolutionary movements in Macedonia, crossed into Thessaly and pushed on to east-central Greece. However, his course was checked in Boeotia, at Vasilika, where hundreds of Ottomans were killed and his army was dissolved. A month later, when Tripolitza was being captured, Omer Vryoni left east-central Greece. The klepht warfare, so pernicious for the enemy, proved effective. Another Ottoman expedition was not to be realized until spring 1822.