The calm of the sleepy Swiss city of Basel is punctuated twice a year by the less-than-rowdy visitors to its two main events: Art Basel and the Jewellery and Watch Fair. Last month, the situation was far from normal, with grim-faced Swiss riot police cordoning off tracts of the medieval centre in preparation for Euro 2008.

Several matches, including Switzerland versus the Czech Republic and Germany versus Poland, were scheduled to coincide with Art Basel. For some in the art world, including the director of the Kunsthaus Baselland, which was forced to shut its major show early, the football was an imposition.

For others, it was an opportunity to kill two birds with one stone. The surprise appearance of the fair was just such a collector - the Russian billionaire and owner of Chelsea Football Club Roman Abramovich, who flew into town a week before the opening of his private art museum, CCC Moscow.

The fair was full of the owners or curators of private museums, including the Rubells and Marty Margulies from Miami, to senior representatives of the 13 Wurth museums and the Essl Collection in Vienna.

Private-museum collectors are becoming so prevalent that dealers of the most sought-after artists are becoming more cautious about the long-term intent of some of these institutions.

But for many, the big thrill was the arrival of Brad Pitt who, along with Abramovich, was blamed for the noise from two private jets that woke up the city at 1.30am on the morning of Art Basel's preview.

Still, the film star's presence, spending hours at the main fair and the Design Miami Basel satellite, added a touch of glamour to the art world's favourite fair.

Jane Morris is an arts journalist and editor