Why would a Northern Irish Protestant, raised in a staunchly loyalist community, hitchhike through Catholic Europe on the trail of medieval celtic monks? Why is the seaside town of Bangor in Northern Ireland largely responsible for Europe becoming a Christian continent? What role did an Ulsterman play in the creation of the European Union, and what can be done today to break down walls and bring people together? Who was Columbanus of Bangor and why are present-day librarians from all over the world indebted to him? Why does God not like zebras, has Murphy\'s Law anything to do with chaos theory, and why are the Germans the reason Ireland had to wait 1,900 years to get decent, straight roads? Answers to all these questions can be found within these pages, the story of the European travels of sixth-century saint, Columbanus - and of a twenty-first century sinner, the book\'s author. Weaving history, politics, theology, and personal narrative together in a humorous and readable way, Sloan tells the fascinating story of Columbanus and his legacy in uniting Europe. Profound moments of reflection and insight are punctuated by hilarious episodes: of breakfast with Vikings, of an attack by monster bees - and lunch with a talking horse When the Saints go Marching is funny, thought-provoking, informative, inspiring and challenging - and all without being preachy.