The Scottish Saltire, also known as the St. Andrew’s Cross, is one of the oldest national flags in the world. It was named after St. Andrew, the patron saint of Scotland, who was crucified on an X-shaped cross (saltire) in the city of Patras in Achaea around 60 AD.
According to legend, in 832 AD, King Angus of the Picts and Scots had a vision of a white saltire in the sky before a battle against the Angles. Interpreting it as a sign of divine support, they adopted the symbol, and subsequently won the battle.
The Saltire began to be used as a national symbol of Scotland during the 12th Century. In the 15th Century, the use of the Saltire was formalized, and it became widely recognized as the national flag of Scotland. Circa 1542, it was included in Sir David Lyndsay of the Mount’s Register of Scottish Arms.
The flag itself consists of a white saltire on a blue field. The shade of blue has varied over time, but in 2003, the Scottish Parliament recommended Pantone 300 as the standard shade. The white saltire represents the cross of St. Andrew, and the blue background symbolizes the sky.
Today, the Saltire remains as a powerful symbol of Scottish identity and heritage.
Sources
Wikipedia - Flag of Scotland
Scotland.com - The Flag of Scotland
Scottish Flag Trust - The Legend of the Saltire