Rumours abounded in the spring and summer of 937 from merchants and traders that Scots are mobilising troops and that Norse Irishmen are pressing men and building a huge fleet.
(Late September? Olaf Guthrithsson was known to be suppressing revolting Irish and press-ganging recruits in Dublin in August- “breaking their ships”)
In common with William of Malmesbury, the Egils Saga refers to a land invasion of Northumbria:
‘…the king of the Scots got a great army together and then went south into England, plundering everywhere as soon as he came to Northumberland [sic]’.
The OE poem describes only the battle rather than the whole campaign but while Anlaf G is several times associated with the sea or boats, Causantín is not, and of his retreat from the battlefield the poem records simply that he-
‘went in flight north into his own land’.
John of Worcester stated that Anlaf arrived with a fleet at ‘the urging’ of Causantín: …On any reasonable construction of this sentence Causantín had to be elsewhere than with Anlaf.
The Durham Historia Regum made explicit the separation implied by the earlier chronicler, suggesting no link between the northern kings and a fleet;
‘…King Athelstan…put to flight King Anlaf with 615 ships and also Causantín, king of the Scots, and the king of the Cumbrians, with all their host’
THE CAPABILITY OF FLEETS IN THIS ERA?
William of Malmesbury gives an account of the later King Edgar’s royal fleets in the 960's-70's;-
“ Every summer, immediately after the Easter festival, he [Edgar] used to order a gathering of the ships on every coast, his custom being to go with the eastern fleet to the western part of the island [Britain], and when that had been patrolled, to make with the western fleet for the northern, and then with the northern fleet for the eastern, his virtuous purpose to find out whether pirates were giving any trouble.”
