About 5 miles from my apartment, there is an old church that was built on a fifth-century Roman mausoleum in what is now the small town of Saint-Prex on Lake Geneva. It is one of the oldest churches in the country. Three apses and a bell tower were added in the 12th century. Shortly afterward, the church became a stop on the pilgrimage to Santiago de Compostela, the Way of St. James. It was transformed into a Protestant church in 1536 when the Bernese expelled the Savoy and now sits empty most Sundays. The history of Christianity in Europe, its displacement of paganism and subsequent growth and decline, can be traced in the building itself.