Image: "The calling of Peter and Andrew", c. 1308-1311, by Duccio di Buoninsegna (c. 1255/60 - 1318/19), Italian medieval painter from Siena.
Source: Duccio [Public domain], via Wikimedia Commons
According to the Bible, Andrew, the brother of Simon Peter, was born in Bethsaida on the Sea of Galilee (in the modern Israel). They both were fishermen, and when Jesus called them as followers Andrew was the first to recognize him as the Messiah, and became his devout disciple.
After 50 days after the death of Jesus Christ the apostles got a gift of healing, prophesy and speaking in different dialects about the great affairs of God. Andrew got his territory to spread Christianity, and so he preached in the areas of modern Bulgaria, Macedonia, Greece, Albania, Serbia, Kazakhstan, southern Russia, Ukraine, Azerbaijan, parts of Georgia and Romania. He is believed to be the author of various miracles and resurrection of the dead in the lands where he preached.
St. Andrew is considered the first preacher of Christianity in Georgia. In Romania there are archaeological evidences for his activity on the territory - the carved symbols of ancient Christianity, found in a cave Basarabi (town of Murfatlar).
In Ukraine there is a legend about St Andrew, who sailed across the shore and erected a cross on the hill, telling a prophecy about the future great city on that place, where later Kyiv was founded.
Once Andrew got to the pagan country of Achaea (today the northwestern regional unit of Greece) and converted many citizens into the Christian faith, including the wife of the governor. The angry ruler, after a long discussion with the apostle, condemned him to the crucifixion. In this way Andrew was martyred at the city of Patras in AD 60. He was crucified on a cross of the form called Crux decussata, or "saltire", now commonly known as a "Saint Andrew's Cross". According to some texts he was bound, not nailed to the cross, and that very shape was chosen by himself, not feeling worth to be put on the same kind of cross as had been used for Jesus. After the crucifixion Andrew lived two days more suffering, but still preaching to the people who gathered around.
Image: "The Martyrdom of Saint Andrew", by the Limbourg brothers (Herman, Paul, and Johan; fl. 1385 - 1416), Dutch miniature painters from the city of Nijmegen.
Taken from http://www.wikipaintings.org/en/limbourg-brothers/the-martyrdom-of-saint-andrew