The opening text of the film boldly proclaims that, "During the 17th Century the Spanish Main was overrun with pirates, foremost of whom was Edward Teach, the evil and immortal Blackbeard."

Blackbeard's career as a pirate captain lasted two years, from 1717-1718 (in the 18th century). While he did plunder in the Caribbean, basing himself in the Bahamas (not Jamaica), more of his time was spent in the North American colonies, where he managed to ingratiate himself to Governor Eden of North Carolina, who is even alleged by "Captain Johnson" to have presided at Teach's nuptials (to his 14th wife, a girl of 16).

Governor John Vaughan of Jamaica, who had succeeded Morgan's cohort Sir Thomas Modyford, did indeed persecute his Lieutenant Governor, having Morgan brought repeatedly before the Jamaican Council on miscellaneous charges of which the accused was always acquitted thanks in part to his popularity. [In fact, what Vaughan suspected Morgan of was not overt piracy but that "he was clandestinely arranging private commissions with his old friend Governor d'Ogeron of Saint Domingue and taking 10 percent of the profits" (Cawthorne).] (Meanwhile, after spending two years in the Tower of London without a trial, Modyford had also been sent back to Jamaica to serve as chief justice.) Rather than sailing the high seas, Morgan spent increasing amounts of time haunting the taverns of Port Royal, and Vaughan finally succeeded in having him "suspended from office for disloyalty and drunken disorder" (Cordingly, 1996). Vaughan was eventually recalled as governor, to be replaced temporarily by Morgan himself, but Morgan was in turn removed from office in 1682 by returning interim governor Sir Thomas Lynch.

As for the film's setting of Port Royal, on June 7, 1692 (four brief years after Morgan's death yet a full quarter century before the start of Blackbeard's career), the city known to contemporaries as "the richest and wickedest city in the New World" was obliterated first by an earthquake and then by the tidal waves that followed, taking Morgan's ceremoniously interred remains with them. What little of the city that was not permanently submerged was rebuilt (on the site of present-day Kingston) and ceased to be a haven for pirates. By Blackbeard's time, the hotbed of piracy in that region had been relocated to the then-ungoverned island of New Providence in the Bahamas, known today as Nassau, which Blackbeard and over 500 of his contemporaries, including close associates Stede Bonnet, Benjamin Hornigold, and Charles Vane (none of whom is mentioned in the film), made their home base. When former privateer Woodes Rogers was appointed governor of the Bahamas in 1717 and set about his successful campaign to suppress piracy, Blackbeard relocated his base of operations to North Carolina.

There was, in fact, a pirate captain named Worley or Worsley who sailed from New York in 1718. He was clearly not a goofy lummox, though, as he managed to begin his career with a crew of only eight and soon captured several prizes before he was killed in battle off South Carolina. Governor Johnson personally led the attack against him due to the state of high alert in Charleston following recent raids by Blackbeard and his associates.

Meanwhile, Israel Hands, real-life ship's master and pilot (two positions which required considerable technical knowledge and skill) under Blackbeard is mentioned in passing but conspicuously absent from the film. His competence was at least such that he was trusted with command of Blackbeard's prize, the Adventure. However, Hands left the crew after Blackbeard, playing a practical joke, lamed him with a gunshot to the knee. It is through his eyewitness testimony that we know anything reliable about Blackbeard's shipboard exploits. (Robert Louis Stevenson borrowed Hands's name for the character of the coxswain aboard the Hispaniola, formerly Captain Flint's gunner, in Treasure Island, and he turns up again in another Robert Newton movie: Long John Silver's Return to Treasure Island.)

In 1666, Dutch pirate Edward Mansvelt (anglicized to Mansfield) was indeed elected "admiral" of a fleet of 600 buccaneers (referred to in later literature as the "Brethren of the Coast") at the urging of Governor Thomas Modyford of Jamaica, who sought to protect his island from Spanish attacks. However, even in 1663, when he took part in Sir Christopher Myngs's campaign against the Spanish, Mansfield was described not as "the blackest pirate whatever," but as an "elderly man," and he died in 1667, shortly after returning from the campaign. Henry Morgan (nephew of the late Colonel Edward Morgan, who had also been in Modyford's employ and was said by Exquemelin to have served as Mansfield's vice-admiral) was promptly elected his successor. (Since Morgan was born in Wales many years later than Mansfield, it is highly unlikely that he could have been uncle to Mansfield's daughter, if indeed he had one living in the Caribbean.)

Further, the film's premise in which Mansfield's daughter meets Morgan the lieutenant-governor/pirate hunter must have taken place sometime between 1676 and 1682, while her betrothed, Charles Bellamy, did not begin pirating until 1717, about the same time as Blackbeard.

Blackbeard is dogged by Edward/Robert Maynard; however, Maynard makes clear early on that it is not Blackbeard but Morgan he is after. [Warning: plot spoiler!] Later on, Blackbeard is cruelly done in by his own disgruntled crew on a Caribbean island.

In reality, Blackbeard was hunted down, along with his crew, and killed in a bloody and dramatic hand-to-hand shipboard battle in November 1718 at Okracoke Inlet in North Carolina. The attack was led by Lieutenant Robert Maynard, by order of Governor Spotswood of Virginia. Even after sustaining five gunshot wounds and twenty deep stab wounds, including a slashed throat and a bullet in his chest (fired at close range), Blackbeard fought on fiercely, breaking Maynard's sword in two before finally succumbing to his injuries and falling dead on the deck. His decapitated head was hung from the bowsprit of Maynard's sloop, while his body was flung overboard. (Legend has it that it swam several times, Rasputin-like, around the ship before sinking to the bottom!) By the end of the piracy trials, only two of Blackbeard's crew survived: one man who had joined the crew only the day before and Israel Hands.

In the words of Patrick Pringle, Blackbeard is "probably the most maligned pirate in history. He ... never fought if he could avoid it. ... He did not terrorize his prisoners, and there is not a shred of evidence to show that he ever ill-treated one of them. He threatened murder at [the siege of] Charleston, but did not keep his word when the time-limit expired [and the medicines he demanded were not delivered]. When he took prizes he usually put the crews ashore and burnt their vessels. If this was not possible he merely took the cargoes and let the men keep their ship, although it would have been safer to sink her with all hands. ... Blackbeard fought bravely at the end, but this was the only occasion on which he ever had to fight."