The Summer Of The Danes by Ellis Peters

Set in the 12th century, this historical mystery follows Brother Cadfael, a Benedictine monk with a knack for solving crimes, as he embarks on a journey to Wales. Accompanied by a young monk, he finds himself entangled in a web of political intrigue and personal vendettas when they encounter a Danish fleet. As tensions rise between the Welsh princes and the Danes, Cadfael must navigate the dangerous waters of diplomacy and deceit to uncover the truth behind a murder, all while maintaining peace and order in a land on the brink of war.