What is the difference between European and standard pillow shams?

"European" pillows are square, usually 26" x 26", and used as decorative accents. Standard pillows come in various sizes, but are rectangular and intended for sleeping. Shams for each kind of pillow can be simple or ornate, but in a typical set of bed linens, the European sham will have a more decorative purpose and may even be made of a different, coordinating fabric pattern.