The Albannach/Scots were caught and stood to face their persuers in the area of Markle, near modern East Linton. This is to the north of the modern village of Athalstaneford (which was rested on higher groundin the 18th century), where the Peffer, which flows into the Firth of Forth at Aberlady, forms a wide vale. Being then wholly undrained, the Peffer presented a major obstacle to crossing and the two armies came together at the ford near the present day farm of Prora (one of the field names there still is in the Bloody Lands).
Fearing the otcome of the encounter, King Angus led prayers for deliverance and was rewarded by seeing a cloud formation of a white saltire (the diagonal cross on which St Andrewhad been martyred) against the blue sky. The King vowed that ifwith the saint's help he gained victory then Andrew would thereafter be the patron saint of Scotland. The Scots did win and the Saltire became the flag of Scotland