Headache makes up a major chapter in the writings of the great medical authors of the Byzantine period (324 to 1453 CE). This important period was the natural link between antiquity and the Renaissance, one that is greatly appreciated by researchers of the history of medicine. A detailed analysis was made of the original Greek medical texts, of the most important Byzantine physicians in order to relate their descriptions to the recent classification according to the International Headache Society criteria. The "Byzantine Classification" of headache follows the ancient tradition, adopting the main classifications already described. Byzantine authors passed on the earlier knowledge, adding some subcategories and some more descriptions and therapeutic options. In many cases, subcategories and descriptions are reminiscent of the modern classification and corresponding criteria.