I have been researching the Rosemary Sutcliff historical novels and retellings for children’s books which have been turned into TV and radio programmes. Sea Dragon was a version of Blood Feud made for TV in 1990. The TV series gets an average 8.1 (of 10) rating from users at ImDB. The essence of the plot is this: sold into slavery to the Northmen (Norsemen) in the tenth century, a young Englishman becomes involved in a blood feud which leads him to Constantinople and a totally different way of life.
The United States newspaper the Washington Post commented, when the book was first published in 1976, that:
Sutcliff’s gift is to recreate an era, in this case the 10th-century voyages of the Northmen and the rise of Byzantium, so convincingly that her readers accept without question the different mores of another time. The violence of the blood feud between two families set off by an accidental killing seems inevitable. No writing down here, no anachronisms, just a glorious sense of history, a sense of knowing how it was.
The Director of the TV film was Icelander Ágúst Guðmundsson; the adaptor David Joss Buckley. The lead actors were Graham McGrath (as Jestyn), Bernard Latham (as Gyrth) and Janek Lesniak (as Thormod). Other cast members were: Baard Owe as Haki; Øystein Wiik as Thraud; Pat Roach as Aslak; Trine Pallesen as Ayrun; Lisa Thorslunde as Thormod’s Mother; Eiry Palfrey as Sister Gytha; Holly Aird as Ffion; Lasse Spang Olsen as Herulf; Martin Spang Olsen as Anders; and Anna Massey (who sadly died in 2011) as the Prioress.