Boccaccio
Giovanni Boccaccio, (1313?-1375) an Italian author now mainly famous for the Decameron

Facsimile
A facsimile is a book which is an exact copy of the original

Indulgence
A letter of indulgence grants forgiveness for all or some of the buyer’s sins, in return for payment and in principle conditional on repentance

Liturgy
The liturgy is the collection of formulas and other texts which make up the religious services of the Christian church

Manuscript
A manuscript is a handwritten book

Mercer
A mercer is a merchant who deals in textiles

Penance
Penances were the punishments imposed by the Church on people after they had confessed their sins. They were generally fasts, sexual continence, pilgrimages or floggings. In the 15th century it was increasingly common to pay money instead of performing the penance.

Vernacular
The vernacular languages are the languages actually spoken by a group of people, often in contrast to Latin and ancient Greek.