Xerxes had now arrived within sight of Mount Olympus, the northern boundary of what was properly called Hellas; after a march through nothing but subject territory, with magazines laid up beforehand for the subsistence of his army, with additional contingents levied in his course, and probably with Thracian volunteers joining him in the hopes of plunder. The road along which he had marched was still shown with solemn reverence by the Thracians, and protected both from intruders and from tillage, even in the days of Herodotus.[72] The Macedonian princes, the last of his western tributaries, in whose territory he now found himself,—together with the Thessalian Aleuadæ,—undertook to conduct him farther. Nor did the task as yet appear difficult: what steps the Greeks were taking to oppose him, shall be related in the coming chapter.