This year both Portugal and Morocco issued a set of 2 stamps characterized by a common design.
This is called a Twin Issue since it's a joint issue where design and issue date (26 August 2007) are identical for both countries involved.
PORTUGAL / MOROCCO
As you can see by the images, there is a similar design between:
- Left Portuguese stamp 0,30Euro and the right stamp of 7,8Dh from Morocco. They depict the Tower El Kamra in Assilah. Town conquered by the Portuguese in 1471 and posteriorly recovered by Moulay Ismaîl Ben Chrif in 1691.
- The other 2 stamps show the Silves Castle in Portugal. The town was occupied by the Moors in 713. The town was finally taken from the last Muslim King Ibn Afan by Paio Peres Correia, Grand-Master of the order of Santiago in 1242. Some images of the Castle here.