It was at this time also that James and John were called, and Andrew appears with them and his brother at the head of the list of the twelve apostles. It was he who brought to our Lord the boy with the five barley loaves and two fishes at the feeding of the five thousand; and he and Philip told our Lord of the gentiles who had come asking if they might see him (John 12:20-22). 

We have various accounts of the later life of St Andrew, but they are fragmentary and mainly not dependable. The Christian historian Eusebius tells us that he preached in Scythia. St Gregory Nazianzen says that he went to Epirus, St Jerome that he was in Achaia--and there seems a genuine tradition that he was indeed in Greece.

The medieval tradition that he finally arrived at Constantinople and founded a church there is apparently unfounded; and the details of his martyrdom are equally uncertain. He is said to have incurred the enmity of the proconsul at Patras in Achaia, and to have been bound to a cross, where he remained two or three days preaching to the people who came to watch him, before he died.

Andrew is the patron of both Russia and Scotland. His connection with Russia is based on a tradition that in his missionary journeyings he preached in that country, reaching the city of Kiev in what is now the Ukraine, which was the center of the conversion of Russia in the eleventh century. Legend connects him with Scotland. It says that in the fourth century the guardian of the relics of Andrew at Patras was told in a dream to take part of them to a place that would be shown to him. He was led to what is now St Andrews in Scotland; he built there a church and preached to the heathen people. The St Andrew's cross-'saltire' or X-shaped-of Scottish heraldry, often supposed to have been the form of cross on which Andrew was martyred, does not, in fact, seem to have been associated with the saint before the fourteenth century. (Harper’s Bible Dictionary)