Emperor
The first Austrian Emperor was the last Holy Roman Emperor Francis II. In the face of aggressions by Napoleon, Francis feared for the future of the Holy Roman Empire. He wished to maintain his and his family's Imperial status in the event that the Holy Roman Empire should be dissolved, as it indeed was in 1806 when an Austrian-led army suffered a humiliating defeat at the Battle of Austerlitz. After which, the victorious Napoleon proceeded to dismantle the old "Reich" by severing a good portion from the empire and turning it into a separate Confederation of the Rhine. With the size of his imperial realm significantly reduced, Francis II, "Holy Roman Emperor" became Francis I, "Emperor of Austria". The new imperial title may have sounded less prestigious than the old one, but Francis' dynasty continued to rule from Austria and a Habsburg monarch was still an emperor ("Kaiser"), and not just merely a king ("König"), in name.
Domus Aurea (Antioch)
Julian moved to Antioch in 362, soon after becoming the sole ruler of the eastern empire, following the death of Constantius II. He was the last non-Christian ruler of the Roman Empire, and chose Antioch as his headquarters, partly to lay plans for his proposed campaign against the Persians and partly to further his attempt to restore the eastern empire to Hellenism. He had the body of Saint Babylas removed from the martyrium near the temple of Apollo at Daphne, because he thought that it had silenced the oracle of Apollo. When the temple burned down, shortly thereafter, Julian was furious, suspecting the Christians and in response closed the Great Church, removing its liturgical vessels. This act effectively brought his attempts to restore Hellenism in Antioch to an end.