In 803 and 810 he made a treaty with Charlemagne, by which the limits of the two empires were amicably fixed.
To the petty states this meant only a change of masters; they now became part of one of the largest empires of antiquity.
There was no attempt to overwhelm whole empires by pouring into them masses of troops, but commerce was combined with territorial acquisition, and a continuity of European interest secured by the presence of merchants and settlers.
But he had little success, and soon concluded a treaty by which both empires promised toleration to the worshippers of the two rival religions, Christianity and Zoroastrianism.
Sayce, The Ancient Empires of the East, Herodotus with introductions and appendices (1883; an attempt to prove the unveracity of Herodotus, especially in regard to the extent of his travels, which has found little support amongst more recent English or German writers); R.