Medieval Greek refers to the form of the Greek language used from the fall of the Byzantine Empire in the 5th century until the early modern period around the 15th century. This period saw significant changes in grammar, vocabulary, and pronunciation, influenced by Latin, Turkish, and Italian due to various political and cultural interactions. During this time, Medieval Greek was the language of literature, philosophy, and administration in the Byzantine Empire. Important works, such as religious texts and historical accounts, were written in this form, laying the foundation for the modern Greek language spoken today.