The rise of several western powers between 1081 and 1143 was clearly of significance for Byzantium's Balkan frontier, and while the Normans and crusaders were handled effectively, encroachments by both Hungary and Venice went unchecked. Alexius I's general indifference to the north-western Balkans stood in sharp contrast to his efforts to restore and retain imperial authority in Paristrion and Dyrrachium. He was willing to allow Venice and Hungary to control Dalmatia and Sirmium so long as both were his allies. His only consistent policy was to play one power against the other whenever either seemed to have gained the upper hand, often veering between positions suddenly. This did not check the independent ambitions of either the Hungarians or Venetians, and after a cooperative start both began to expand their interests without paying great attention to Byzantine concerns. John II pursued a similar hands-off policy. His priorities lay in the east, and his forays into the Balkans were brief shows of strength. They appear to have been successful, within the limits John set, but our knowledge of them is coloured by the preoccupations of Byzantine authors writing later and with different agendas. Nevertheless, by 1143 the Venetians had secured control over the whole northern Adriatic, by sea and land. The Hungarians had extended their influence further into Sirmium and the Slavic lands of the northern Balkans, and had secured recognition in the central Dalmatian cities of Šibenik, Trogir and Split.