Byzantine literary accounts (i.e., John of Ephesus, etc.) mention the Slavs raiding areas of Greece during the 580s. According to later sources such as "The Miracles of Saint Demetrius", the Drougoubitai, Sagoudatai, Belegezitai, Baiounetai, and Berzetai laid siege to Thessaloniki in 614–616. However, this particular event was actually of local significance. A combined effort of the Avars and Slavs two years later also failed to take the city. In 626, a combined Avar, Bulgar and Slav army besieged Constantinople. The siege was broken, which had repercussions upon the power and prestige of the Avar khanate. Slavic pressure on Thessaloniki ebbed after 617/618, until the Siege of Thessalonica (676–678) by a coalition of Rynchinoi, Sagoudatai, Drougoubitai and Stroumanoi attacked. This time, the Belegezites also known as the Velegeziti did not participate and in fact supplied the besieged citizens of Thessaloniki with grain. It seems that the Slavs settled on places of earlier settlements and probably merged later with the local populations of Greek descent to form mixed "Byzantine-Slavic communities". The process was stimulated by the conversion of the Slavic tribes to Orthodox Christianity on the Balkans, during the same period.