Sentence:  Sebastian, a profound student of such lore, had long believed that the book was a mere medieval legend; and he had been startled as well as gratified when he found this copy on the shelves of a dealer in old manuscripts and <WSD>incunabula</WSD>. 
Meaning of the word marked with <WSD> tags:  A book, single sheet, or image that was printed before the year 1501 in Europe.