The flag of St Andrew, Patron Saint of Scotland. St Andrew is supposed to have been crucified on two diagonal beams known as the Saltire. In the 8th Century (736AD) King Angus defeated the Saxons under a blue sky with the white cross of St Andrew.
After the Battle King Angus appointed the cross of St Andrew as the badge of the Picts.
In Medieval times, nations used the banners of national Saints and before long the acceptance of the Saltire as the national flag of Scotland became common.
In 1385 as the Scots prepared to invade England, an order was issued that every man should wear the Saltire before and behind.