A Horologion, or Book of Hours, contains the outline of the services (aside from those relating to the Eucharist) of the Greek Orthodox church. It includes services particular to specific times of day, such as Matins and Vespers. Additional 31214, made in the 12th century, is a typical example of a horologion. It is small in size (160 x 110 mm) and therefore easily transportable. While it has clearly been well-used over the years, the presence of illuminated headpieces, as well as decorated initials, indicate that its original owner was a person of some means.
It formerly belonged to the Rev. Greville John Chester (1830–1892), priest of St Jude’s, Sheffield, and was purchased by the British Museum in 1880.