The oldest surviving accounts are two: one among the manuscripts collected by Colbert and willed to the King, now in the Bibliothèque Nationale, Paris, the other in the Harleian Mss in the British Library, London. They state that the relics of Andrew were brought by one Regulus to the Pictish king Óengus mac Fegusa (729–761). The only historical Regulus (Riagail or Rule) — the name is preserved by the tower of St Rule — was an Irish monk expelled from Ireland with St Columba; his date, however, is c. 573–600. There are good reasons for supposing that the relics were originally in the collection of Acca, bishop of Hexham, who took them into Pictish country when he was driven from Hexham (c. 732), and founded a see, not, according to tradition, in Galloway, but on the site of St Andrews. The connection with Regulus is, therefore, due in all probability to the desire to date the foundation of the church at St Andrews as early as possible.
Another legend says that in the late 8th century, during a joint battle with the English, King Ungus (either the Óengus mac Fergusa mentioned previously or another king of the same name (820–834)) saw a cloud shaped like a saltire, and declared Andrew was watching over them, and if they won by his grace, then he would be their patron saint. However, there is evidence Andrew was venerated in Scotland before this.
A third theory as to Andrew's connection with Scotland is that, following the Synod of Whitby, the Celtic Church felt that Columba had been "outranked" by Peter. They therefore decided that the patron of the Celtic Church would now be Peter's older brother. While a satisfying piece of folklore, there is no more evidence for this than any other theory.
The 1320 Declaration of Arbroath, which declared Scottish independence from England, cites Scotland's conversion to Christianity by St Andrew, "the first to be an Apostle", as evidence of Scotland being held in especially high regard by God.
Numerous parish churches in the Church of Scotland and congregations of other Christian churches in Scotland are named after St Andrew.