He started scouring the Internet. He found it strange that Calment didn’t mention the cholera epidemic that ravaged Arles in 1884; that, upon moving out of her apartment, she had enlisted a relative to burn her personal effects; that her grandson had called her Manzane, a portmanteau of maman and a childish pronunciation of her first name. Calment had often equivocated in conversations about her family. (“That’s a useless question!” she once barked, when an interviewer asked if she’d loved her grandson.) An identity card from the nineteen-thirties said that she had black eyes, but, at the end of her life, one report recorded them as gray. Furthermore, according to the card, Calment’s height, in middle age, had been a hundred and fifty-two centimetres. If that was true, then how could she have still stood a hundred and fifty centimetres tall at the age of a hundred and fourteen, as one record suggested, having lost almost no height? Meanwhile, her signature, Zak thought, had changed tremendously over the years, acquiring a looping “J.”

There were the van Gogh stories, in which she’d mixed up her husband and her father. In addition, Calment had told her validators that she had been escorted to school by a maid named Marthe Touchon. Census documents confirmed that a Marthe worked for the Calment family in the early nineteen-hundreds. She was listed as Marthe Fousson, a variation on the name that seemed reasonable, given that Calment had difficulty enunciating at the end of her life. Yet, when Zak tracked down Fousson’s birth certificate, he found an odd discrepancy: Marthe Fousson was ten years younger than Jeanne Calment and thus couldn’t very well have taken her to school.

Zak started fiddling with Photoshop, examining Calment’s lower lip, the skin on her chin, the tip of her nose, and the shape of her skull at various ages. Soon he had developed a theory: the person the world had known and fêted as Jeanne Calment was actually her daughter, Yvonne.