 He spent the remaining years at the École de Droit, Paris, and applied himself to Roman law at the universities of Berlin and Heidelberg, graduating with a doctorate in law from Heidelberg in 1867.Wallace accepted a private invitation to visit Russia, having a strong desire to study the Ossetes, a tribe of Iranian descent in the Caucasus.Living in Russia from early 1870 until late 1875, Wallace found the Russian civilization far more interesting than his original Ossetes.