The River Shannon brought conquering Vikings to this area in the ninth century; today, King John’s Castle serves as a dramatic reminder of Limerick’s tumultuous medieval history. Now, however, the battles are on the rugby field, a game that is the passion of this sports-loving city. The people of Limerick are also proud of their cultural treasures, which include the works by Da Vinci, Renoir and Picasso in their magnificent Hunt museum, and more recently, the writings of favorite son Frank McCourt of “Angela’s Ashes” fame.