The exhibition of the work, on loan from its anonymous German buyer, finished last Sunday, transforming attendance figures at this normally straight-faced German museum. During those 11 months the Staatsgalerie attracted 180,000 visitors, about double the usual, according to Charlotte Mischler, the museum’s head of communications. It stayed open until 10 p.m. for the last five days to cope with demand.

This is quite a turnaround. Fifteen years ago Banksy, a young upstart street artist from Bristol, England, was smuggling his works into museums as pranks. Now, they can be the official stars of the show, accompanied by guided tours and lectures.

How has Banksy, the archetypical artist-provocateur, gotten here? None of it has happened by accident. Banksy’s rise and rise is the result of years of meticulous control of his message, his market and, most importantly, his mystique.

The enormous popularity of Banksy’s brand of urban art has given the cultural establishment, increasingly jittery about perceptions of elitism, plenty to think about. The Staatsgalerie Stuttgart has asked the question: Is Banksy a historically significant artist? If he is — and for many that is a very big “if” — what will be his legacy?