Below is a neatly postmarked cover from Zaragoze to Tudela. I include highlights of the Baeza and the rate. Notice how the oils used in both of these markings have discolored the paper. This effect is very difficult to reproduce by forgers. Here are quick links to the three covers described in this article: The first cover from Seville (Sevilla), and is postmarked in 1842 / The second cover from Barcelona, and is postmarked in 1844 / The third cover from Zaragoza, and is postmarked in 1845.