Julian (Born Flavius Claudius Julianus in 331 AD, died 26 June 363 AD) was Roman emperor from 361 to 363 AD, as well as a notable philosopher and author in Greek. Raised as a Christian, he later embraced Neoplatonic Hellenism and became a devotee of the Sun.

The following is from Wikisource - Hymn to King Helios:
“Emperor Julian followed Plotinus and Iamblichus in making the supreme principle the One (ἓν) or the Good (τὸ ἀγαθὸν) which presides over the intelligible world (νοητὸς κόσμος), where rule Plato's Ideas, now called the intelligible gods (νοητοὶ θεοί). Iamblichus had imported into the Neo-Platonic system the intermediary world of intellectual gods (noeroi theoi). On them Helios-Mithras, their supreme god and centre, bestows the intelligence and creative and unifying forces that he has received from his transcendental counterpart among the intelligible gods. The third member of the triad is the world of sense-perception governed by the Sun, the visible counterpart of Helios. What distinguishes Julian's triad from other Neo-Platonic triads is this hierarchy of three Suns in the three worlds: and further, the importance that he gives to the intermediary world, the abode of Helios-Mithras. He pays little attention to the remote intelligible world and devotes his exposition to Helios, the intellectual god, and the visible Sun.”