It's a functional and quite practical film that portrays Flynn as looking exhausted and struggling. Who would’ve imagined that Errol Flynn’s final swashbuckler—an actor celebrated for countless fictional heroes—would be one loosely inspired by a real person’s life? This largely forgotten movie presents an obviously fabricated scenario, but it's built around the actual historical figure known as the Black Prince. As someone with a background in history, I’ll attempt to clarify some aspects of this… As most people are likely aware, England and France engaged in several wars during the Middle Ages, frequently referred to as the Hundred Years' War. The central issue was control over territories now located in present-day France and the right of English monarchs to the French throne. Centuries earlier, Duke William of Normandy, a vassal of the French kings, conquered the English crown, becoming king of England while still remaining a French duke and lord of many lands there. Over time, through marriages of subsequent kings, territories like Brittany, Anjou, Loire, and Aquitaine were added to the holdings. When the French king died without a direct heir in 1328, his sister asserted her son’s claim—Edward III of England—as nephew and closest male relative. French nobles, citing a law barring inheritance through female lines – the Salic Law – rejected this and instead placed a cousin of the deceased king, the Count of Valois, on the throne. The ensuing war featured major battles mostly won by the English, led by Edward himself and his son, known as the Black Prince due to the color he used to paint his armor. His military skill also established him as a significant figure in the Hundred Years' War. The script takes historical foundations and crafts an appealing, romantic fiction with themes of courtly love, chivalry, and adventure. The film does work, but it’s clear from the start that we are seeing a contemporary interpretation of what the era and conflict might have been like. There are noticeable inaccuracies, particularly in how the characters behave; these struck me more than any issues with their accents. It's hard to understand why an English Crown Prince would simply consider posing as a mercenary for a noble far less important than himself, all because of a woman—it’s something that wouldn’t have been conceivable within a medieval mindset. Errol Flynn is noticeably past his prime in this film. He looks very weary and it's apparent that his regular drinking had taken its toll on him. He also seemed to lack the vitality and youth required for the role he was given. He was well aware of this, and it seems he only accepted the part because of the money involved. Peter Finch is adequate but has little to do, and Joanne Dru was effective as a romantic interest, though her function appears limited to being rescued. From a technical standpoint, the film possesses some strengths, primarily because the production made good use of sets and costumes from previous films in order to save money—and these were high-quality pieces. The cinematography is also quite beautiful, with its color, light, and pleasant camera movement. While the fight scenes are obviously choreographed precisely, they still manage to achieve their intended effect minimally.

Source on TMDB