c. 1400 CE
The book of hours is a popular medieval Christian devotional book written in Latin. It is the most common type of surviving medieval illuminated manuscript. Such books would contain texts, prayers, and psalms to be read at specified hours of the day. The leaves are illuminated with pure gold. First the letters to illuminated would be covered in chalk to the desired height, then gold would be melted and applied over top the result giving the letter a raised look while using the least amount of gold necessary.