Perhaps the most thrilling find yet is a double-palimpsest from Egypt, a 10th-century manuscript written in Syriac (a Semitic language of the Christian East) on pages that contain a twofold layer of Latin texts. One is a hitherto unidentified grammatical text from the 7th century, written above another 5th-century Latin text preserving fragments of the otherwise lost historical work of the 2nd-century Granius Licinianus, whose writing is known only from these recycled pages.
A nice post on the recycling of parchment in the Middle Ages with a look at some of the British Library’s palimpsests on the Medieval manuscripts blog, September 14, 2016.