The Warlord Chronicles is a trilogy of books written by Bernard Cornwell about Arthurian Britain. The story is written as a mixture of historical fiction and Arthurian mythology.

• The Winter King ISBN 0140231862
• Enemy of God ISBN 0140232478
• Excalibur ISBN 0140232877

The books have been published by Penguin and Michael Joseph in the United Kingdom and by St Martin's Press in the United States, in hardcover and paperback editions, each with different ISBNs.

Cornwell's thesis is that Post-Roman Britain was a difficult time for the native Britons, being threatened as they were by invasion from the Anglo-Saxons in the East and raids from the Irish in the West. At the same time, he argues, they suffered internal power struggles between their petty kingdoms and friction between the old Druidic religion and newly-arrived Christianity.

The story is written as if it took place in the early Middle-Age Britain as described in the original Welsh legends, with appropriate types of technology, culture, warfare, and attitudes. Cornwell also weaves later mythological additions such as Guinevere and Lancelot into the plot.

The protagonist of the series is Derfel Cadarn, a Saxon brought up as a Briton by Merlin, the greatest of all Druids. In the course of the story, Derfel becomes a great warrior and one of Arthur's lieutenants in his war against the Saxons. Merlin, meanwhile, concerns himself with trying to restore the old gods of Britain.

The Warlord Chronicles is often considered to be among Cornwell's best work, being acclaimed for both its storytelling qualities and its accuracy in portraying contemporary life.

Cornwell's portrayal of Merlin as a lecherous, driven, irreverent druid is particularly memorable, as is his unflinching descriptions of Dark Age barbarities. Also interesting is his solution to the problem of integrating the magic of the Arthurian mythos in the context of historical fiction: he leaves room for the reader to take the "magic" depicted in the story at face value or to interpret it as a mixture of coincidence, psychology, and primitive technology.