Dominicans. Catholic Church. Antiphonary: manuscript, approximately 15th century. (Technically, this image is of the letter I. The first recorded distinction of a J from an I is around 1524.)
Creative Commons Attribution License (CC-BY)
One of 29 images featured on collectible cards printed and distributed free in the University of Dayton Libraries in October 2019 in honor of American Archives Month.
The book in which this image appears is available in digital form in this repository.