Elagablaus is, as QuintusCinna referred, a very interesting but sad historical character.
He is a perfect example of what would be third century religiosity: deep and irrational beliefs, that appealed to the heart and the feelings rather than they did to the mind. That was the principle of the old roman religion, and of the old roman society.
There is a very good ( tough biased, as all XIX th century historic production is) report on his coming to power. it's Gibbon's famous " Fall of the Roman Empire". he gives us a very "pre raphaelite" tale of his ascent and fall from power.
Julia Maesa was shrewd politician, with a wealth beyond imagination. She, and Julia Domna were descendents form an ancient royal family from Emesa, deeply connected to the cult of the sun god. In addition to the wealth their family was allowed to keep, they also managed the properties of the temple of Ela Gabal.
When Caracalla was murdered, his deposer committed the ultimate mistake of letting Julia Maesa go free (because she, like her sister, was very endeared by the roman senatorial class) with all of her possessions. With the pretense that her daughters ( Soemia and Mammea) had given birth to the sons of Caracalla and Geta, she amassed an army to go against Macrinus, and ultimately defeated him. This was a very bold move. Not only because of the danger of loosing everything (even her life), but also because she exposed her daughter to the public opinion as whores, an epithet that would eventually cost their lives in the long term. You, by the time they said to have bore child by Caracalla and Geta, both of them were married to other men.

Going back to Elagabal, his attempt to merge religions ( that clminated in the rape of the vestal virgin Aquila severa, and the marriage betwen the paladium and the sun stone of Emesa), was followed afterwards by Alexander Severus, tough in a much more discrete fashion. Secretly this empereor is said to have worshiped even the christian God.