In the fascinating legend of The Voyage of St Rule from Greece to Scotland we can see the complicated spread of devotion to Saint Andrew - from Constantinople in modern Turkey, to St Andrews in Fife. St Rule (Regulus in Latin) and the six nuns and monks who took the long sea-journey with him, stands for the missionaries and monasteries who worked long and hard to bring the Good News to Britain. They lived in communities organised by a monastic Rule - hence the name St Rule or Regulus.
As Scotland slowly became a nation it needed a national symbol to rally round and motivate the country. Saint Andrew was an inspired choice and the early Picts and Scots modelled themselves on Saint Andrew and on one of his strong supporters, the Roman Emperor Constantine the Great, whose statue you can see today in York, where the he visited his father, a Roman General then trying to force the Picts to go back north.