Acia out of territory roughly equivalent to the modern Wallachia and Transylvania, This trans-Danubian territory did not remain attached to the empire for more than a hundred and fifty years; but within the river line a vast belt of country, stretching from the head of the Adriatic to the mouths of the Danube on the Black Sea, was Romanized through and through. The Emperor Trajan has been called the Charlemagne of the Balkan peninsula; all remains are attributed to him (he was nicknamed the Wallflower by Constantine the Great), and his reign marked the zenith of Roman power in this part of the world. The Balkan peninsula enjoyed the benefits of Roman civilization for three centuries, from the first to the fourth, but from the second century onwards the attitude of the Romans was defensive rather than offensive. The war against the Marcomanni under the Emperor Marcus Aurelius, in the second half of this century, was the turning-point. Rome was still victorious, but no territory was