Al-Mu'tadid was unable, however, to restore effective caliphal control north of the Jazira in Transcaucasia, where Armenia and Adharbayjan remained in the hands of virtually independent local dynasties. Ibn Abu'l-Saj, who was now the caliphal governor of Adharbayjan, proclaimed himself independent around 898, although he soon re-recognized the Caliph's suzerainty during his conflicts with the Christian Armenian princes. When he died in 901, he was succeeded by his son Devdad, marking the consolidation of the semi-independent Sajid dynasty in the region. In 900, Ibn Abu'l-Saj was even suspected of plotting to seize Diyar Mudar province with the co-operation of the notables of Tarsus, after which the vengeful Caliph ordered the latter arrested and the city's fleet burned. This decision was a self-inflicted handicap in the centuries-long war against Byzantium; in recent decades the Tarsians and their fleet had played a major role in the raids against the Byzantine frontier provinces. While a Syrian fleet under the Byzantine Greek convert to Islam Damian of Tarsus sacked the port of Demetrias around 900, and Arab fleets would go on to wreak havoc in the Aegean Sea over the next two decades, the Byzantines were strengthened on land by an influx of Armenian refugees, such as Melias. The Byzantines began to expand their control over the border regions, scoring victories and founding new provinces (themes) in the former no-man's land between the two empires.