Former Sotheby’s Europe chairman Simon de Pury has won a legal battle with his childhood friend over the sale of one of the world’s most expensive paintings to the emir of Qatar, reports The National.

Britain’s highest court ruled on Wednesday for de Pury, and Michaela de Pury, in a long-running dispute with Swiss art collector Ruedi Staechelin who had reportedly backed out of a handshake deal to pay a commission to Simon de Pury, a board director at Gucci, for his role in the sale of Paul Gauguin’s Nafea Faa Ipoipo? (When Will You Marry?).

Staechelin had appealed an earlier court decision to pay the de Purys a $10 million commission.

The painting sold for $210 million to Qatari Sheikh Tamim bin Hamad Al Thani almost five years ago.

In a statement, de Pury said: “The integrity of a handshake deal in the art world has been upheld.”