Guido Reni was a gambling addict and zealot who took guff from no one... not even the Pope.
Reni was one of the first artists to receive the tell-all biography treatment. The guy needed a lot of help. The only woman he could stand was Mom and every other female was barred entry to his home, which dovetails nicely into his insurmountable fears of witchcraft and being poisoned. One woman's garment got mixed up in his laundry and that, apparently, was an attempt to poison him. He also hated swearing and told people off if they used a double entendre. Contemporaries maintained that he remained a virgin to his deathbed, mostly because he'd be 'like marble' in the company of his beautiful young models. Considering his implausible fear of witchcraft, it's more likely he was just trying to keep an eye on all the witches trying to get at him.
He was also a gambling addict. Though he was second only to Peter Paul Rubens in fame, gambling dominated his cash flow. He'd even deign to accompany the Caravaggisti on their drunken, pagan fueled exploits if it meant a night of cards. Considering how many women and double entendres he endured you'd think it'd be quite the chore. Guido even changed his style of painting later in life to accommodate his gambling debt. Later paintings were pumped out fast, sacrificing quality for the bottom line. He even charged by the unthinkable method of an hourly wage to ensure his gambling could continue unabated. Even though he had money problems, he was a giver. Friends could count on a handout from Guido, and charities were well-heeled by his anonymous donations.
Even at his worst, though, his paintings were widely sought after. Popes and royalty clamored for his work, though they'd regret it if he got pissed off. Reni was temperamental. For even perceived offences, he'd retaliate by finding any reason to refuse finishing a commission. Whatever got people off his back, really. Fellow artists felt the prickle as well resulting in huge fallouts with friends Albani and Domenichino, with teachers Calvert and Carracci, and with gambling buddy Caravaggio. The Pope wasn't even immune to his wrath.
After hearing a rumor that one Cardinal Giovanni Battista Pamphilj had talked trash, Reni used the religious man's face in a painted depiction of Satan. Yeah, that's a little risky, considering the Pamphilj family was one of Italy's most powerful. But, by a happy coincidence, Reni's painting was for Cardinal Antonio Barberini. There was a Hatfield & McCoy situation between the Barberinis and Pamphiljs, on top of a personal nemesis thing with the Cardinals Antonio and Giovanni Battista. When Giovanni Battista personally told Reni to knock it off with the Satan funny business, nothing happened. Reni simply claimed that Satan appeared to him in a dream and it wasn't his problem that the Cardinal (and future Pope) looked so much like the Prince of Darkness.
Are there any examples of Reni's work that were directly influenced by Caravaggio?