New study suggests vast erasure of medieval writing—up to 60% of works and 95% of manuscripts lost

A study in PNAS Nexus uses stemmata (family trees of manuscripts) and computer simulations to estimate losses in medieval writing, finding that up to 60% of medieval literary works and more than 95% of manuscripts have vanished over the centuries. By modeling copying, destruction, and random disasters (e.g., fires, wars, Black Death), researchers show that texts were most at risk early on and that surviving copies typically stem from later branches; the original forms of famous works like the Song of Roland may be gone. The approach could help quantify losses in other historical texts as well.