Which patron saint is associated with a white cross on a blue backdrop?

Okay, let's talk about patron saints and flags! The question is about which saint is linked to a white cross on a blue background. That's St. Andrew. He's the patron saint of Scotland, and the white cross on a blue field is the Scottish flag, also known as the Saltire. Now, here's the interesting bit: St. Andrew, one of Jesus's apostles, is said to have been martyred on an X-shaped cross in Greece. This distinctive diagonal cross became his symbol. Scotland adopted St. Andrew as their patron saint way back in the Middle Ages, and the Saltire has been used as Scotland's flag since at least the 15th century. So, while St. George is associated with England (and his red cross), St. Patrick with Ireland (though he's more about shamrocks than a specific flag), and St. David with Wales (and a yellow cross), it's St. Andrew whose diagonal white cross flies proudly on Scotland's blue background.