Yarhibol was the sun-god of Palmyra, the radiant attendant of Bel, the divine witness of oaths. His name probably means 'Lord of the Spring' (yarḥi being a variant of an Aramaic word for moon, but used in Palmyra for the spring of Efqa, the great oasis-spring that was the source of the city's water), and he was the divine guardian of the spring. Around the spring was the original sanctuary of Yarhibol — predating the great Temple of Bel by perhaps a century — and his priesthood was responsible for the rites that maintained the spring's sacred character.
By the first century of our era, Yarhibol had been associated with Bel and with the solar imagery of the developed Palmyrene pantheon. He stood on Bel's right hand in the great cult-relief of the Temple of Bel (preserved photographically before the destruction of 2015), depicted as a beardless youth in radiant armor, with rays around his head. The function had shifted: Yarhibol was now the sun-god, the bringer of daylight, the witness of justice. His association with the spring of Efqa remained, but it was overlaid by the broader solar significance.
His role as oath-witness made him a central deity of Palmyrene legal life. Contracts, treaties, and important agreements were sealed by oath in his name; the inscriptions record his function repeatedly. The Palmyrene Tariff of 137 of our era — the great bilingual inscription regulating customs duties, now in the Hermitage Museum in St. Petersburg — names Yarhibol as one of the divine guarantors of the customs system. So the god of the spring became the god of the oath, the divine warrant of contractual fidelity in the great trading city.
After the sack of Palmyra by Aurelian in 273 of our era and the Christianization of the eastern empire, Yarhibol's cult was extinguished. His sanctuary at the Efqa spring was abandoned, his role as oath-witness was taken over by Christian saints, and the rites at the spring continued in attenuated form (with Christianized formulas) until the medieval period. The spring itself, the original sacred site, dried up in the 1990s as a result of overpumping of the regional water table — an environmental loss that severed the last physical link to the original Palmyrene cult.


