The series premiered in 1937.
This is a continous historic and epic adventure story which unfolds in medieval times around the court of legendary King Arthur. Although the precise events are figments of Foster's imagination both plots and drawings are meticulously constructed to such an extent that locations, population, clothing and buildings seem very realistic. The main story is that of a young Nordic prince, Valiant, who is constantly travelling around to uphold law and order in King Arthur's realm, but his travels also bring him to many other locations. The story is remarkable thereby that the main characters actually age; Valiant starts out as a teenager, but later on he marries and has children which we also follow as they grow up. The full title of the series is Prince Valiant in the Days of King Arthur.

Harold R. (Hal) Foster was a Canadian-American cartoonist. His most famous creation was the Prince Valiant strip.

Foster studied at the Chicago Art Institute, supplemented with night classes at the National Academy of Design and the Chicago Academy of Fine Arts. His artistic influences included E.A. Abbey, Howard Pyle, Arthur Rackham, Maxfield Parrish, J.C. Leyendecker, James Montgomery Flagg, and N.C. Wyeth. Foster worked as a staff artist for the Hudson Bay Company and then as an illustrator before getting involved with graphic adaptation of Edgar Rice Burroughs's Tarzan novels. Foster's sense of realism, composition, draftsmanship, and his fluid anatomy brought a new "fine art" feel to adventure comics. Another Foster trademark that appeared for the first time in comics was the use of captions instead of word balloons.

Eventually, wishing to do something original, Foster began working on a character of his own: Derek, Son of Thane. Hal later changed the strip's title to Prince Arn and King Features Syndicate's general manager, Joseph Connelly, finally re-christened it Prince Valiant. Hal decided early on that his hero would be a Knight of the Round Table and made tens of thousands of notes and sketches covering the main character's life from childhood to old age. Hal never included a locale that he had not personally visited for thematic accuracy.

In 1936, Foster pitched Prince Valiant to William Randolph Hearst, who had long wanted Foster to do a comic for his papers. Hearst was so impressed that he promised Foster the ownership of the strip if he would start the series, a very rare offer in those days. The first episode of Prince Valiant in the Days of King Arthur (the full title) appeared on February 13, 1937. The tales were so epic that Edward, The Duke of Windsor called Prince Valiant the "greatest contribution to English literature in the past hundred years."

Prince Valiant became one of the most successful comic series of all time, winning the prestigious Banshees' "Silver Lady" award (1952) and both the National Cartoonists Society's coveted "Reuben" award (1957) and "Gold Key" award (1977). When he was 73, Foster was elected to membership in Great Britain's Royal Society of Arts - an honor very few Americans have received.

In addition to the Reuben and Gold Key awards, Foster received a number of other recognitions from the National Cartoonist Society, including the Story Comic Strip Award in 1964, the Special Features Award in 1966 and 1967, and the Elzie Segar Award in 1978. He was inducted into the Will Eisner Hall of Fame in 1996, and in 2005 he was inducted into the Joe Shuster Canadian Comic Book Creators Hall of Fame for his contributions to comic books.

Hal Foster died in 1982. Prince Valiant, which still runs in newspapers today (2008), is now drawn by artist John Cullen Murphy.