Book #4 in the series, Adventures with Sister Philomena, Special Agent to the Pope. Even nuns get to take a holiday! In this adventure, Sister Philomena, her niece Delaney, and nephew Riley, are invited to Siena, Italy for the famous Palio horse race and festival. Their vacation plans abruptly change when they stumble upon mysterious documents while visiting the childhood home of Saint Catherine of Siena. It's possible they have found a centuries-old letter written by Saint Catherine along with a ransom note addressed to the Pope. Of course they must investigate! Their search for answers takes them on a fast trip across Europe to Avignon, France, and the famous Palace of the Popes. In the course of their investigation, the children learn about Saint Catherine and the history of the Church in the 1300s when the papacy was forced to flee from Rome to Avignon for safety. The book features peeks into the cultures of both Italy and France and teaches a few Italian and French words and phrases. - from Amzon