A view across the River Shannon in Limerick, County Limerick, Ireland

© Piotr Machowczyk/Shutterstoc

Info. A view across the River Shannon in Limerick, County Limerick, Ireland

The Irish city of Limerick lies on the River Shannon, the longest river in Ireland. We’re looking across the river at the historic part of Limerick, a medieval section once walled off by the Vikings and known today as King’s Island. That’s King John’s Castle on the left, built on the order of King John in 1200. Over on the right is St Mary’s Cathedral, which was founded in 1168 and is the oldest building in Limerick still in use. History suggests the presence of earlier settlements in the area before the Vikings conquered it and destroyed Irish public records. The earliest map of Ireland, produced in 150 CE by historian and overall polymath Ptolemy, shows a place called ‘Regia’ at the same site as King’s Island.