The Eastern Empire attained its acme in the sixth century, during the
reign of Justinian, A.D. 527-565. It was he who built the great Church
of Saint Sophia at Constantinople, now a Mohammedan mosque. His chief
service to mankind, however, was the codification of the laws in the
great system of Roman jurisprudence called the Civil Law, forming the
basis of the law in European states at the present day.