The yellow-brown coloration formed in the degradation process of linen fabrics has been studied by Raman spectroscopy. Aqueous extracts from documented linens from the Egyptian XIIth Dynasty (ca. 4000 y BP) and Kasr-el-Yahud (ca. 1350 y BP) have been used to investigate the chemical basis of the degradation process; the pale-yellow crystalline material isolated from these extracts shows evidence of OH, C=C, C-C, and hydrocarbon groups. Several possibilities for the ring scission of cellulose under archaeological conditions are addressed.