News of the gathering Norwegian fleet soon reached Alexander II, who appears to have made straight for the western coast, diverting his attention to the now rapidly developing crisis. On 28 May, Alan is recorded in Alexander II's presence at Ayr, where the Scottish royal forces appear to have assembled. It was probably May or June when Óspakr's fleet rounded the Mull of Kintyre, entered the Firth of Clyde, and made landfall on Bute, where his forces successfully stormed and captured a fortress that is almost certainly identical to Rothesay Castle. The "Flateyjarbók", "Frísbók", and "Skálholtsbók" versions of the saga specify that the castle fell after three days of battle, and that three hundred Norwegians and Islesmen fell in the assault. By this stage in the campaign, the fleet is stated to have reached a size of eighty ships, a tally which may indicate that Óspakr's fighting-force numbered over three thousand men. Reports that Alan was in the vicinity, at the command of a massive fleet, are stated to have forced the Norwegians to withdraw to Kintyre. Whilst the "Eirspennill" version of the saga numbers Alan's fleet at almost two hundred ships, the "Flateyjarbók", "Frísbók", and "Skálholtsbók" versions give a tally of one hundred and fifty. These totals suggest that Alan commanded a force of two thousand or three thousand men. Having withdrawn his fleet to Kintyre, Óspakr took ill and died, presumably succumbing to injuries sustained from the assault on Bute. According to the saga, the king's death was bitterly lamented amongst his followers.