They roamed the Spanish Main in their armed ships, flying the skull and crossbones. And, though many of the most famous were British, they plundered the cargoes of Spanish and British ships alike.

Fuelled by copious quantities of rum, walking the plank was a favourite means of disposing of their enemies, and their battered bodies bore witness to their violent lives. Black eye-patches dramatically covered useless eyes; Long John Silver famously lost a leg and acquired a wooden one (as well as a parrot); and in Peter Pan’s Neverland, Captain Hook’s name came from the terrifying replacement he found for his missing hand.

Such cliched images of pirates have been embedded in our minds by classic literature and films. And, of course, there is the legendary language and the childhood jokes they spawned: “Why are they called pirates? Because they aargh.”

As with all the best literary and dramatic genres, the pirate story continues to evolve. Johnny Depp’s magnificent, strutting, camp caricature Captain Jack Sparrow in the film series Pirates of the Caribbean is now the ultimate pirate in popular culture.

The relationship between pirates and their national governments was always ambivalent. France, Britain and later the US all employed privateers (ships issued with a licence or letter of marque) to prey upon the ships of their enemies. There was a fine line between the privateer and the pirate. British governments disavowed privateers and pirates when it suited them, but continued to find them occasionally useful.

Henry Morgan, who was alternatively privateer and pirate, ended up as a knight, an admiral and governor of Jamaica. But such Caribbean buccaneers of the late 17th and 18th centuries were not the only pirates to terrorise the high seas or make raids on peaceful coastal settlements throughout history. Vikings can be considered pirates - when they raped and pillaged, if not when they conquered and settled - and there have been Chinese, Japanese and Indian pirates.

When Gilbert and Sullivan wrote their comic opera The Pirates of Penzance, the juxtaposition of pirates and a peaceful Cornish peninsula, which was at the time growing in popularity among Victorian holidaymakers, may have seemed playful. But a century earlier, a different sort of pirate had raided villages in Devon and Cornwall.

The Barbary corsairs were certainly pirates, though some could claim the status of privateers when capturing the ships of enemies of the Ottoman sultan. From their bases in Islamic North Africa, the corsairs operated throughout the Mediterranean and, from the early 17th century, posed a major threat both to shipping and to towns and villages. In their galleys and square riggers, they captured thousands of ships. Long stretches of the coasts of Spain and Italy had to be abandoned, while those fortified hill towns - those which modern tourists so delight in now - illustrate the absolute terror the invaders engendered in those who built them.

Pirates ventured further west and shipping between Britain and Ireland suffered from their depredations. Baltimore in Ireland was sacked, and along the southwestern English coast villagers and seamen were vulnerable to attack and capture.

It was capture that inspired the greatest fear, for this meant slavery and being lashed while manacled to an oar as a galley slave, or being sold in the slave markets of North Africa or the Middle East. More than a million captives were sold as slaves and, although this was only about a tenth of the number of Africans sold in the transatlantic slave trade, these white slaves constituted a sizable proportion of the maritime European states.

Ransom was another lucrative sideline and wealthier captives could hope to be released if their relatives paid up. But this was not an option for impoverished seamen and villagers, for whom slavery was the usual fate. The idea of European Christians being enslaved by Islamic captors aroused considerable horror, but what was most disturbing was the idea of white women being subject to the sexual appetites of foreign men. This aroused revulsion mixed with a frisson of titillation, giving rise to paintings depicting slave markets and a sub-genre of the literature of piracy, an early example of which was The Lustful Turk, or Lascivious Scenes from a Harem, published in 1828.

The threat from the Barbary corsairs ended in 1830 with the French conquest of Algiers. In any case, Caribbean piracy was in decline by then. The navy proved as effective in limiting piracy as it was in ending the slave trade. But this was not the end of the pirate. Piracy never ceased, but slightly altered its shape, reappearing whenever maritime security declines and rich pickings are available.

The modern pirate takes advantage of the small crews on merchant ships and lurks wherever there are narrow shipping lanes, as in the Gulf of Aden or the Strait of Malacca. Piracy also flourishes in waters contested between states and in areas such as the Indian Ocean, where countries such as Somalia are no longer able to control their coastlines.

The big prizes are the oil tankers, whose owners are prepared to pay millions in ransom, but the increasing number of yachts making long voyages also provides an easy target. As with the corsairs of old, ransoms are a lucrative part of the trade, and though British government policy is against the paying of ransoms, it has been suggested that as much as $1 million was paid for the release of the captured yachting couple Paul and Rachel Chandler in 2010.

Although men such as Captain Kidd, Edward Teach (Blackbeard) and Irishwoman Anne Bonny acquired something of a glamorous reputation, there is little romance to be found in the modern Somali pirate, with his motor-launch, Kalashnikov and willingness to kill his captives if a ransom is not forthcoming.

A. W. Purdue is visiting professor of history at Northumbria University.

WHAT ELSE?

Key stage 1: Morning rising

Colouring templates and challenges, which make great fillers and starters for a pirate unit, have been provided by erylands. bit.lyPRQ0Vl

Key stage 2: Treasure trove

Dcukface shares all manner of pirate resources, from facts about the Jolly Roger to tales about tankards of ale.

bit.lyOxFIHL

Key stage 3: Fact not fiction

Delve into the world of Elizabethan piracy with a history lesson from danrock.

bit.lyOENX6E

Key stage 4: Ode to the sea

Try some pirate-themed poetry to celebrate Talk Like a Pirate Day with a recording of the ballad of John Silver shared by Spoken Verse. bit.lyPUsDYT

Key stage 5: White slavery

Share Project Gutenberg’s e-books White Slaves and the Oppression of the Worthy Poor and discuss the slave industry with pupils. bit.lyPESYs7.