An accomplished young horsewoman who loved fencing and male attire, the 17th-century Swedish Queen Christina was anything but a conventional princess. And she kept springing surprises on her court and country: after just a decade on the throne she abdicated, converted to Catholicism and moved to Rome. Once there, she put herself forward as a candidate for the post of queen of Naples, opened a public theatre and scandalised the Holy See by a liaison with a cardinal. Bridget Kendall follows Christina's adventures with biographer Veronica Buckley, and historians Stefano Fogelberg Rota and Therese Sjovoll. Photo: Christina of Sweden by Jacob Heinrich Elbfas, 1640s