emperors acknowledged their devotion to Ahura Mazda in inscriptions, as attested to several times in the Behistun inscription, and appear to have continued the model of coexistence with other religions. Whether Darius was a follower of the teachings of Zoroaster has not been conclusively established as there is no indication of note that worship of Ahura Mazda was exclusively a Zoroastrian practice. According to later Zoroastrian legend (Denkard and the Book of Arda Viraf), many sacred texts were lost when Alexander the Great's troops invaded Persepolis and subsequently destroyed the royal library there. Diodorus Siculus's Bibliotheca historica, which was completed circa 60 BCE, appears to substantiate this Zoroastrian legend. According to one archaeological examination, the ruins of the palace of Xerxes bear traces of having been burned. Whether a vast collection of (semi-)religious texts "written on parchment in gold ink", as suggested by the Denkard, actually existed remains a matter of speculation. Alexander's conquests largely displaced Zoroastrianism with Hellenistic beliefs, though the religion continued to be practiced many centuries following the demise of the Achaemenids in mainland Persia and the core regions of the former Achaemenid Empire, most notably Anatolia, Mesopotamia, and the Caucasus. In the Cappadocian kingdom, whose territory was formerly an Achaemenid possession, Persian colonists, cut off from their co-religionists in Iran proper, continued to practice the faith [Zoroastrianism] of their forefathers; and there Strabo, observing in the first century B.C., records (XV.3.15) that these "fire kindlers" possessed many "holy places of the Persian Gods", as well as fire temples. Strabo further states that these were "noteworthy enclosures; and in their midst there is an altar, on which there is a large quantity of ashes and where the magi keep the fire ever burning." It was not until the end of the Parthian period (247 – 224) that Zoroastrianism would receive renewed interest. Late antiquity As late as the Parthian period, a form of Zoroastrianism was without a doubt the dominant religion in the Armenian lands. The Sassanids aggressively promoted the Zurvanite form of Zoroastrianism, often building fire temples in captured territories to promote the religion. During the period of their centuries-long suzerainty over the Caucasus, the Sassanids made attempts to promote Zoroastrianism there with considerable successes, and it was prominent in the pre-Christian Caucasus (especially modern-day Azerbaijan). Due to its ties to the Christian Roman Empire, Persia's arch-rival since Parthian times, the Sassanids were suspicious of Roman