The Avars, traditionally a nomadic people, desperately needed both shelter and pasture for their livestock, but the route to Pannonia was blocked by impassable mountains covered with thick forests: the Carpathian range. It was in the critical winter of 566-567 that the Avars, stuck in what is now eastern Germany, were sent feelers by Alboin, the strong ruler of the Lombards and brother-in-law of Sigebert, who sought an alliance to crush his old enemies the Gepids. These last ones, by chance, controlled the only practical way from the Lower Danube to the craved Pannonian pastures. So in 567 (see Lombard–Gepid War (567)) king Cunimund's Gepid kingdom was attacked by two directions: from the west came the Lombards, from the north, through Moravia and the Danube, the Avars. Bayan crushed Cunimund's forces and made a cup from his defeated enemy's skull as a present (and warning) for his ally Alboin (who is famously quoted as having forced Cunimond's daughter Rosamund, whom he had taken as war bride, to drink from it, sealing his own fate). Then the Avar horde marched against Sirmium, by now firmly held by Gepid remnants and a Byzantine garrison led by general Bonosus. In the meantime large numbers of Slavs settled in Pannonia in the wake of the Avars; and in 568 Alboin and his Lombards deemed it wise to move for the half-ruined but promising lands of Italy where they would establish a long-lasting kingdom. They concluded however a treaty with the Avar Khagan so as they could reenter parts of Pannonia and Noricum (Austria) if they chose so in the future, then departed with large numbers of the vanquished Gepids and a host of other Germanic tribes.