Career
He has published over twenty collections of essays on history (especially of Slavs and Vikings), archaeology, marine exploration and material culture. He is known for his theory of a Viking ancestry of Mieszko I, the first historical sovereign of Poland.He was one of the consultants being interviewed in the five-episode documentary film "The Vikings" by Paul Russell and Andrea Vogt (production: Millstream Films 2015, distribution: Viasat History).