To engage the English, the Scots had to advance downhill, cross a large area of marshy ground and then climb the northern slope of Halidon Hill. The Battle of Dupplin Moor the previous year had shown how vulnerable the Scots were to arrows. The prudent course of action would have been to withdraw and wait for a better opportunity to fight, but this would guarantee the loss of Berwick. The armies encountered each other's scouts around midday on 19July. Douglas ordered an attack. The "Lanercost Chronicle" reports: