Women's and youth rights in Byzantium: Under the Byzantine
   Empire (which was a Christianization of Roman law, providing
   more equality for women), the earliest marriage ages were 15 for
   men and 13 for women. 15 for men and 13 for women were
   considered the age of discretion.
   " both being desirous and having obtained the consent of their
   parents, shall be contracted either by deed or by parol. "
   [1]http://legacy.fordham.edu/halsall/source/byz-marr726.html
   Byzantine law is quite interesting. Much of it was quite
   progressive, especially considering Justianian II and his wife,
   the Empress Theodora set down these rules in the 6th century AD,
   she was equally powerful and influential to him, and their laws
   stayed intact and in force for over 800 years.

References

   Visible links
   1. http://legacy.fordham.edu/halsall/source/byz-marr726.html