After the Romans developed codex around the first century, the design of books was changed into the form we are familiar with nowadays, which was folded and sewn together and covered with leather. Since then, the painted images have progressed from cave arts into books and scrolls.
Illustrations and picture books’ progress stepped forward in the Middle Ages (generally considered from the fifth century to the fifteenth century) because of the religions. Churches and monks played key roles in distributing religious books. These religious books had many forms, such as Apocalypses, Graduals, and Gospels. Some of them were with illustrated pages. Nevertheless, there were some other books with illustrations in them during the period, such as secular