It’s not our job to flatter the vanity of the famous. So meet my Andy Warhol and Jean-Michel Basquiat | Anthony McCarten

As his new play opens, the eminent writer on where documentary ends and drama begins

I still own a painting that I purchased at a flea market in Los Angeles in 1993. I got it cheap; $25 and it was in the back of my clapped-out convertible . It turned out to be a copy of Bronzino's Portrait of a Young Man with a Book. In 16th-century Florence, if you wanted your portrait painted then he was your man, for one simple reason: he made you look great. His particular gift - and shrewd commercial decision - was to imbue his wealthy subjects with swagger, confidence and even a certain weight loss.

Three centuries before you could sit before a photographer and more than four before you could take a selfie, rich Florentines would sit still for days and trust that Bronzino would do for them what he'd done for their wealthy neighbours, for Dante. It paid to flatter.