Because their brother Theodore had expressed some unhappiness in regards to his position as Despot of the Morea to John when John visited him on his way to Venice in 1423, John soon recalled Constantine from Mesembria and designated him as Theodore's successor as Despot of the Morea. These plans were thwarted once Theodore changed his mind about the whole affair, but John still wished to place Constantine in the Morea. Though Theodore was now happy to rule in the Morea, he could use some support as he had been beset by enemies throughout the 1420s. In 1423, the Ottomans had broken through the ancient Hexamilion wall, which guarded the Peloponnese, and had devastated the Morea. In addition to the Ottoman threat, the Morea was also constantly threatened by Carlo II Tocco, the Italian ruler of Epirus, who campaigned against Theodore shortly before the Ottoman invasion and again in 1426, occupying territory in the northwestern parts of the Morea. In 1427, John VIII personally set out to deal with Tocco, bringing Constantine and George Sphrantzes with him. On 26 December 1427, the two brothers reached Mystras, the capital of the Morea, and from there they made their way to the town of Glarentza, captured by the Epirotes. In the Battle of the Echinades, a naval skirmish off the coast of Glarentza, Tocco was defeated and he agreed to relinquish his conquests in the Morea. In order to seal the peace, Tocco offered his daughter, Maddalena Tocco (whose name was later changed to the Greek "Theodora"), in marriage to Constantine, her dowry being Glarentza and the other Moreot territories. Glarentza was given to the Byzantines on 1 May 1428 and on 1 July, Constantine married Theodora. The transfer of Tocco's conquered Moreot territories to Constantine made the system of government in the Morea complex. Since his brother Theodore refused to step down from his role as despot, the despotate became governed by two members of the imperial family for the first time since its creation in 1349. Soon thereafter, the younger Thomas (aged 19) was also appointed as a third Despot of the Morea, meaning that the nominally undivided despotate had effectively disintegrated into three smaller principalities. Theodore did not make way for Constantine or Thomas at Mystras.