This Wednesday’s watermark comes once again from the Islamic Manuscripts Collection - one of the papers in Isl. Ms. 863 to be exact. It features a bull's head watermark with a serpent winding around the pole of a cross above.
The bull's head is one of the most widespread watermarks of the European Middle Ages . It exists in myriad variations - with and without certain facial features (such as eyes and nostrils), with and without an additional motif within the head (such as a mane or circle), and with and without an additional motif above or below the head (such as letters, a cross or a serpent on a pole). Of course size and shape of the various motifs may also vary considerably.
12 volumes from the Islamic Manuscripts Collection include at least one type of bull's head watermarked paper. Most of these manuscripts date from the 16th century and are of Anatolian or Egyptian provenance.
The bull's head watermark in the back flyleaf of Isl. Ms. 5 v.2 is quite similar to the watermark appearing in the replacement section of Isl. Ms. 863, but with a different size and shape.
The bull's head watermark in one of the papers of Isl. Ms. 1053 has facial features but no additional motif above.
Of course the placement and visibility of the watermark depend on the size of the manuscript relative to the size of the original sheet of paper, which will have been folded and trimmed to suit the desired size of the finished volume. The bull's head watermark in the paper of Isl. Ms. 535 falls across the fold of each bifolium, so it's necessary to look closely near the gutter to see it. Only half of the watermark is visible at a time.
Looking closely across the fold will help determine whether or not the bull's head has any additional motif above or below. Keep in mind that the two folios will not necessarily be adjacent to each other.
So keep your eyes in the gutter and your outlook bullish. Enjoy your hunt for bull's head watermarks!
 And it was chosen for the title of an excellent booklet and catalogue introducing watermarks and their study, Bull's Head and Mermaid: The History of Paper and Watermarks from the Middle Ages to the Modern Period.