During art-history classes, the importance of his patrimony dawned on him. “My pictures were coming up on the projector all the time,” he recalls. “I said, ‘Oh, that’s mine … that’s mine … ’ ”

At home, Princess Orietta—who died in 2000 at age 78—was “quite dismissive” of much of her august family lineage, her son recalls. “In her very self-effacing way, she called Andrea Doria ‘the pirate of the family,’ ” he says.

The great admiral, in fact, set the precedent for adoption—and squabbling over assets—in the family, during the 16th century (a common enough occurrence in such dynasties, as it happens). With no children of his own, Doria adopted his cousin’s son, Giannettino. Unfortunately, the young man was soon murdered by a rival clan. In retribution, Doria slaughtered the perpetrators and left the ringleader’s corpse on public display for two months before having it thrown into the sea. (Giannettino’s son, Gian Andrea, then became the Doria heir, in 1560.) In more recent times, Jonathan’s mother had “a huge amount of problems,” he recalls, following the death of her father, when she had to contend with numerous relatives “trying to get a slice of the cake.”

These historical lessons no doubt influenced Orietta’s outlook. “She always said, ‘Blood means nothing. Your family is who you love,’ ” her son remembers.

“How wise she was,” he adds, rather emphatically.

Thanks to the straightforward way that his parents told him he was adopted, Doria Pamphilj says, he has no identity issues: “The assuredness with which parents approach the subject will be transmitted to children. If they have any nervousness or awkwardness, the children will pick that up. My parents had none of that. We lived the whole thing with great tranquillity. I can put my hand on my heart and tell you I have no identity issues. I had no reason. They were my parents, and they gave me all the love and affection I needed. That’s all children need.

“They taught me to be myself,” he adds, explaining that they were accepting, too, when he disclosed his homosexuality to them, when he was in his 20s and working at Sotheby’s in London. They were even understanding when he chucked it all in 1990 and moved to Isla Margarita, off Venezuela, with a boyfriend. The pair opened a travel agency and a bar. “We became famous for our coconut drinks,” he says proudly. “In order to grow into a happy adult, one of the most important things is to explore and know yourself.”

When his father began ailing, in 1993, Jonathan came back to Rome to help administer the estate. The gallery, which his parents had opened to the public in 1950, was then in need of significant repairs. Jonathan took the reins and supervised a major renovation, which involved a complete re-hanging of the collection. He also introduced innovations in marketing and technology (such as audio guides), which had never been seen in the then stodgy Italian museum world. When the gallery reopened, in 1998, it was ecstatically praised and even helped catalyze a resurgence within Rome’s centro storico, which was then somewhat down-at-the-heels.

Ars Longa

Although the Doria Pamphilj riches would never have been possible without Innocent X, the real driving force of the dynasty was his sister-in-law, Olimpia Maidalchini. “She was a ruthless, ambitious woman and thus gained enormous power,” recounts Jonathan. “She made a lot of money in unscrupulous ways, one of which was a series of brothels—which were largely patronized by the clergy. They did a good business.”

It was Olimpia’s connoisseur son, Prince Camillo Pamphilj, who formed what is today the core of the picture collection. With an eye toward the future, Innocent X issued a papal bull of fideicommissum on the collection, an entailment which is still legally binding today. The only way to sell or break up the collection would be through permission from the Ministry of Cultural Heritage. Not likely, but, as Jonathan points out, this is Italy: “The most famous expression in Italy is ‘Fatta la legge, trovato l’inganno’ (No sooner have you passed a law than you have found a way around it).”