‘Incunabula’ are items printed up to the year 1500, during the infancy of printing, and are thus of exceptional rarity. The Museum, although rich in 16th-century works, has only three incunabula, or possibly four.
- the Kalendarium of Regiomontanus, an astronomical calendar that also contains printed paper instruments, published at Venice in 1476;
- an incomplete copy of De astrolabio canones (attributed incorrectly to Robertus Anglicus), one of the first printed works on the astrolabe, dating from 1478; and
- another edition of the Regiomontanus calendar, 1482.
All three come from Lewis Evans’s library. The additional candidate is the natural history encyclopedia Hortus Sanitatis, first published in 1491 and famous for its primitive woodcut illustrations; the Museum’s incomplete copy (from the Gunther collection) may be a slightly later edition.