St. Andrew's Cross resembles the letter "X" in the English alphabet and is also referred to as the "saltier" or "Crux Decussata." According to tradition Andrew, the brother of Peter, was crucified on a cross of this shape. Andrew did not feel worthy enough to die on the same style of cross that Christ had died and requested a cross of another shape. His request was granted and he was crucified upside down on a cross which now bears his name. Rather than using nails to secure his limbs to the cross, Andrew was bound to the cross with ropes. His suffering was thus prolonged.

St. Andrew's Cross came into wide use during the Medieval Period and became the national cross of Scotland, since St. Andrew was the patron saint of Scotland.