 During his lifetime, the political and cultural landscape of the Roman Empire changed dramatically and irrevocably for pagan intellectuals, and it did so in disturbing ways. Politically, the Roman Empire was shaken to its foundation by the massive incursion of Gothic tribes into northern Greece (Thrace) and their decisive victory over the imperial army at Adrianople (modern Edirne) in 378. Under Theodosius I, who reigned from 379 to 395, Christianity became the state religion, and in order to strengthen the adopted Nicene orthodoxy, the emperor sought to curtail heresy of any form, both Christian and pagan.