Celebrating 25 years as a recording and touring band, Gregorian head out on a world anniversary tour with an extensive run in North America! Founded by Hamburg-born producer Frank Peterson, the project's distinctive crossover catalogue - modern rock and pop songs reimagined in the style of ancient Gregorian chant - has led to them selling more than 10 million albums, going gold and platinum in multiple countries, and building a repertoire of nearly 300 arrangements spanning classical, pop and rock.