Anastasius Sinaita probably wrote Hexameron in the seventh or eighth century. It shows how early Christians often interpreted the scriptures as spiritual allegory, rather than relying only on the type of literalism that is present today. Anastasius argues that in addition to the literal creation, Moses wrote prophecy of the New Creation through Christ.

I love reading this beautiful book. It is a wonderful compilation of Anastasius' writings on the subject.

http://www.newmoses.org/project.html