After the fall of Missolonghi (April 1826) the Ottomans controlled the majority of central Greece. The only fort remaining in Greek possession was the Acropolis, on which Mehmed Reshid Pasha (Kutahye) now turned his attention. In August 1826 he reached Athens and laid siege. With the surrender of the Acropolis on 24 May 1827, the hope for successful military backing to the Revolution faded away. Central Greece and the majority of the Peloponnese were in the possession of the forces of Kutahye and Ibrahim. After six years of war the successful outcome of the Greek cause now depended on diplomatic effort. Greek hopes turned to Ioannis Kapodistrias, who was invited by the Third National Assembly at the beginning of April 1827 to accept the position of Governor of Greece.

During the ten-month siege of the Acropolis the military tactics followed by the two sides were in general similar to those followed in the siege of Missolonghi. The Ottomans tried to starve the Greeks out, the latter attempted frequent night sorties against the Ottoman positions close to the Acropolis. Makrygiannis distinguished himself in these operations. The construction of underground mines (lagoumia) under the enemy's positions and the consequent explosions was a tactic often crowned with success thanks to the expertness of Kostas Chormovas (Lagoumitzis), who had taken similar action in Missolonghi as well. The main body of the Greek forces had been placed in the environs of Athens behind Ottoman lines. During the ten-month siege encampments were made at Chaidari, Eleusis, Keratsini and Phaliro. The main objective was the occupation of positions that would allow small groups to break the siege and reinforce the besieged. This was accomplished at the end of November 1826 by the philhellene officer Fabvier. Finally, many operations were carried out by the revolutionaries far away from Athens. These operations were often distractions, as at Arachova at the end of November 1826. Some, as at Tourkochori (Tithorea) in the beginning of December, were assaults against Ottoman convoys. In these operations Karaiskakis, who had assumed the leadership of the forces in central Greece, proved outstanding once again.

After the fall of Missolonghi the Greek Revolutionary Administration entrusted the reorganization of the Greek army in central Greece to the chieftain from Rumeli. Karaiskakis may have been questioned but he soon managed to win the acknowledgement of the other chieftains and coordinate opinion, probably for the first time. His participation in battles and his successful campaigns of the last months of 1826 strengthened his position, his reputation and created expectations for a positive outcome of the siege of the Acropolis. However, the assignment of the leadership of the army and fleet to the philhellene officers Church and Cochrane displeased the chieftains. This situation stretched the operational ability of the Greek forces to the limit. The decision of Church to stop the operations at the rear of the Ottomans and to carry out a frontal attack, the death of Karaiskakis on the eve of the Greek attack in a petty clash at Tabouria (Keratsini) and the persistence of Church and Cochrane to carry out the battle on a specific day, all effected negatively the outcome of the operation. The defeat in the Battle of Analatos (24 April 1827) and the disbanding of the army which followed led to the capitulation of the Acropolis a month later. The entire Rumeli was now under the control of the Ottomans.