See the Most Luxurious Medieval Manuscripts in Existence Feel free to judge these books by their covers.

here are treasures to be found inside many medieval manuscripts, from pointing hands to menageries of misshapen animals and sword-wielding rabbits. But in rare instances, there is actual treasure as well. Pearls, diamonds, sapphires, emeralds, and precious metals adorn the covers of a few luxurious texts, some of which are are currently on display at New York’s Morgan Library and Museum.

One particularly notable example on display is the Lindau Gospels, dating to ninth-century France. The intricate metalwork on the back cover only hints at the extravagance of the front cover, which was made nearly a century later. Jewels line the edges and sit on raised clawed legs around a repoussé (metal worked on the reverse side to create an image in relief) figure of Christ. The elevation of the jewel clusters has a practical purpose as well as an aesthetic one; it protects the rest of the cover when the book is open.

In the medieval period, monks usually produced books, but with treasure binding—as this practice is known—metalworkers were employed to emboss patterns of silver and gold and set precious stones. Either the very wealthy or the very pious (or both) commissioned the books, but in the case of the Lindau Gospels, it’s unclear who requested the lavish tome.

A handful of libraries around the world hold such books, but not many treasure-bound manuscripts have survived the centuries. The exhibition brings together the Morgan’s collection, and includes illustrations of jewels and gemstones from inside the manuscripts.