Black Bart, the real pirate of the Caribbean and inspiration for Jack Sparrow's character
And he kept to it. His quick mind was appreciated by Davis, who took to consulting him over navigation and the rig of the sails.
Roberts was older than most of the conscripts on the pirate vessels. Before this gold-plated opportunity, he would have been sailing the triangular route from Britain to Africa to the West Indies and North America for many years, before returning with rich cargoes for his ship-owners. His own wages would have been about £3 a month, with little chance of promotion.
When the Royal James had to be abandoned as unseaworthy off the Gold Coast, the Royal Rover made for the nearby fort of Principe, falsely hoisting the flags of a British man-of-war.
These flags, which Davis always kept stowed in his locker, meant any ship he sailed could approach merchant ships without them realising what treachery was abroad.
Once again, his ruse worked. The Portuguese governor let the Royal Rover enter the harbour, and entertained the pirates - smartly dressed as officers. After a relaxing fortnight, Davis invited the Governor to lunch on board his ship, intending to hold him hostage for ransom.
Meanwhile, however, the Governor had discovered that Davis had been making advances to his wife. He was most displeased and hatched a plan of his own, inviting the pirate captain to call at the fort before lunch for a glass of wine.
On the way, the party were ambushed. Davis, shot through the stomach, fell back, firing his pistols, and died.
A new captain had to be found. Roberts was elected. He had been a pirate for only six weeks, but his shipmates had already recognised his seamanship. One of them said later: "He was chosen not so much for his strength and courage, as for his cunning and knowledge of the seas.
"He could make a quick guess of the bulk and force of any ship that came nigh."
Roberts' first decision - to bombard the fort, set fire to the town, slaughter all the men they could find and steal everything they could carry away - displayed the ruthlessness which was to become his byword.
A contemporary historian wrote: "He accepted of the honour [being elected captain], saying that since he had dipped his hands in muddy water, and must be a pirate, it was better being a commander than a common man."
The first black flag he raised was of himself and Death holding up an hour-glass.
This is the side of Black Bart which Johnny Depp picks up for his captain Jack Sparrow. As cool and brave as he was ruthless, Roberts dressed like a Georgian dandy in ruffs and jewels, velvet breeches, pleated shirts, buckled shoes and silk jackets - all of them looted.
While Jack - and nearly every other pirate we know of - was very partial to a shot of rum, Roberts was teetotal. He disliked drunkenness. Instead of rum, he drank cups of tea.
The secret of Black Bart?s success was patience and tactical flair. He took the Royal Rover to Brazil, where, after a fruitless nine weeks merely looting and burning a couple of slave ships, he encountered 42 Portuguese trading vessels under the escort of two 70-gun warships, at anchor off Bahia.
It was the Lisbon Fleet, an annual armada of incalculable riches. In the darkness, Roberts sailed between the merchant vessels, established which one had the richest cargo and towed it out to sea.
As one of the huge Portuguese warships gained on the Royal Rover, Roberts fired a broadside. Astonishingly, the 70-gunner panicked and heaved to, waiting for the other men-of-war to sail out in support. Roberts escaped with £40,000 in gold coins and jewellery.
But while Roberts was chasing prey off the coast of Guyana, his deputy, left in charge of the Royal Rover, sailed away in an act of treachery, leaving Roberts with one small, poorly armed sloop.
Black Bart?s resources were badly depleted: he had a crew of tough and experienced mercenaries, but his supplies were low and his chances of capturing a prize with this second-best sloop were slim.
Roberts? response was to ensure the loyalty of his men by making them sign a code of conduct.
This was democracy with iron gloves. Each man would have an equal vote in the big decisions and an equal right to food, liquor and prize money. If any man robbed or defrauded another, he would have his nose and ears slit and be marooned.
No gaming was allowed. Lights went out at eight, and any drinking after that had to be done on deck, in the dark. Quarrels would have to be be resolved by duelling. Any man carrying a mistress to sea in disguise would be executed. The musicians (all conscripted) would be on call every day except Sunday.
These rules the pirates swore on the Bible to uphold.
That done, Roberts renamed his sloop the Fortune, later Royal Fortune. He joined forces with a small-time French buccaneer, and together they harassed shipping around Barbados and Martinique, until the local inhabitants financed a well-armed ship which saw off both sloops.
The Fortune limped to Dominica for repairs, with 20 of her crew dying on the journey.
Then, when he set sail for Newfoundland, Black Bart?s luck began to change. He plundered up and down the Atlantic coast, capturing or destroying 27 sloops. Among his bounty was an 18-gun galley in which he proceeded to cause serious havoc.
Roberts despised cowardice. Twenty-two captains of the seized Newfoundland vessels, who had tried to flee at the sight of the black pirate flags and the sound of drums and trumpeters, were summoned to appear before him every morning, at peril of having their ships burned. Some of them he lashed for impertinence.
Meanwhile, his crew made full use of the local brothels, while respectable women kept their doors locked.
By late 1720, Roberts was back terrorising shipping in the West Indies, this time with unassailable firepower - as that 42-gun Dutch vessel found to its cost.
News of the bloody havoc he wreaked aboard travelled far and wide. Roberts then exacted sweet revenge on the locals for their previous defiance.
From Martinique, Roberts used the captured Dutchman and ran up flags to signal that cheap slaves were on offer in St Lucia. He proceeded to ambush the 14 French ships who brought gold dust - the common currency of the slave trade - to pay for them.
Around this time, he captured a 52-gun warship, and finding the Governor of Martinique on board, he hanged him from the yardarm.
The latest of his flagships to be renamed the Royal Fortune was a floating arsenal, including four 12-pound cannons capable of sinking a small vessel with a single shot.
Roberts had virtually forced a standstill in shipping on the Spanish Main, outmanoeuvring the navies hunting him. He now judged it wise to head for West Africa for fresh opportunities.
Off Senegal and Sierra Leone, he continued to destroy or commandeer everything in his path, including two French gunships and the Onslow, a British frigate taking soldiers to Ghana?s Cape Coast Castle, the leading slave bazaar.
Several Onslow soldiers were eager to join the pirates. A few were accepted, but, as landlubbers, they were allowed only a quarter share of any loot.
Roberts had heard that two Royal Navy ships were due to revisit Sierra Leone at the end of 1721, but he was used to such tales.
In any case, he was already getting on for 40 and was planning to hang up his cutlass for good - once he had spent the summer of 1722 unburdening Portuguese vessels of their cargoes of Brazilian gold.
By January 1722, his flagship was in convoy with three other commandeered French warships off the Ivory Coast. As he entered Ouidah, the wealthiest harbour on the coast, all 11 slave ships at anchor there immediately struck their colours, signalling surrender.
Roberts captured the ships and ransomed them back to their captains for 8lb of gold dust each. When one Captain refused him, Roberts burned the ship to ashes, including the 80 slaves in its hold.
He left Ouidah shortly before Challoner Ogle, captain of the 50-gun warship HMS Swallow, came looking for this dastardly pirate who was seriously impeding Britain?s trade with Africa and the West Indies.
It took Ogle three weeks sailing up and down the coast before a tip-off from a captured pirate sent the Swallow to her destination.
On February 5, 1722, Ogle came upon Roberts and his favourites eating lunch by the shore near Cape Lopez in present-day Gabon, while his crews worked on their ships? hulls. Ogle could have taken them then, but his steersman were forced to veer out to sea to avoid a sandbank.
Sniffing booty, Roberts sent out one of the captured French gunships, the 16-gun Ranger, in pursuit of this unknown vessel.
He was out of sight and earshot when the Swallow opened its gunports and blasted the Ranger with a broadside of 32-pounders. By the time the Ranger surrendered, ten men had been killed and 20 more wounded.
The mate of the Ranger went below and fired a pistol into the ship?s gunpowder - but the powder was damp and only succeeded in blowing a hole through the side of the ship, taking the mate with it.
Boarding the stricken sloop, the Swallows? surgeon, John Atkins, was confronted by dead and dying crewmen on a deck awash with blood. He noted dryly that they were "dressed with white shirts, watches and a deal of silk vests".
Some of Ogle?s men coaxed the captured pirate vessel back to harbour, careful of the fortune in plunder in its hold. The Swallow returned to Cape Lopez for a second foray five days later.
Black Bart?s pirates, befuddled from capturing a ship loaded with liquor the day before, were slow to recognise her. When they did, Roberts alerted his crews and prepared for battle.
He dressed in crimson from head to foot, a gold chain round his neck, a curling red feather in his hat, and four pistols roped over his shoulder in a silk sling.
His plan was to sail past the Swallow, risking a single broadside before catching the wind to escape. Instead, the helmsman, panicking, exposed the vessel to a second broadside.
A spray of grapeshot tore out Black Bart?s throat and he slumped dying over a cannon.
While the battle still raged, Black Bart?s body was weighted down and thrown overboard, fulfilling the pirate captain?s wish to be buried at sea.
The Royal Fortune was forced to surrender and 54 of the pirates were later hanged.
Some historians argue that the death of Bartholomew Roberts marked the end of the Golden Age of piracy.
Roberts? own life, for all its flamboyance, demonstrates that there was no "golden age": only the base metal of greed, ruthlessness, debauchery and vicious cruelty, which for 60 years or more bedevilled the Western seas