Chinese artist Ai Weiwei has been named the most powerful person in the art world.
The ranking of the activist, who has been an outspoken critic of China's human rights record, comes after he spent more than two months in detention this summer.
His arrest in April, as he boarded a Beijing flight bound for Hong Kong, prompted a global campaign for his release.
The artist, who recently created 100 million porcelain sunflower seeds for Tate Modern's Turbine Hall, is only the second ever to top the annual Power 100 list, compiled by ArtReview magazine and now in its tenth year.
The magazine said that his "activities have allowed artists to move away from the idea that they work within a privileged zone limited by the walls of a gallery or museum. They have reminded his colleagues and the world at large of the fact that freedom of expression is a basic right of any human being", it said.
"In the process, Ai has promoted the notion that art's real context is not simply 'the market' or 'the institution', but what's happening now, around us, in the real world."
Damien Hirst, famous for his pickled sharks, is the only other artist to have previously topped the list, in 2005 and 2008.
Second place goes to Serpentine gallery directors Hans Ulrich Obrist and Julia Peyton-Jones. They are ranked ahead of Tate director Sir Nicholas Serota, who takes sixth place.
The top 10 also includes Glenn D Lowry, director of the Museum of Modern Art, New York, in third place, while US collector and gallery owner Larry Gagosian, who topped the list last year, is fourth.
Artists Anton Vidokle, Julieta Aranda and Brian Kuan Wood, who run an online art journal, are fifth, US artist Cindy Sherman is seventh, gallery owners Iwan Wirth and David Zwirner are eighth and ninth, and museum director Beatrix Ruf is tenth.