The cannabis plant evolved on the Tibetan Plateau 19.6 million years ago and had to travel 5,000 miles to reach Ireland, only arriving there about 1,000 years ago. After being cultivated and analyzed on the Emerald Isle, it ended up influencing European geopolitics and Western medicine through its two most familiar species, sativa and indica. (No disrespect to ruderalis.) And whether Irishmen in the cannabis industry – from humble farmers to cosmopolitan scientists – realized it at the time or not, they helped to shape the fate of their island.

Cannabis Sativa vs. Cannabis Sativa L. vs. Cannabis Indica

The cannabis sativa plants in ancient Ireland were the sativa L. subspecies, more commonly referred to as hemp. (The sativa subspecies with no “L.” is the one with psychoactive properties.) This name, given by an 18th-century Swedish botanist, simply meant “cultivated.” Then, once a French naturalist traveling in India came into contact with cannabis that looked like sativa but had psychoactive properties, he named it after its content of discovery. Thus, “indica” was adopted, and that’s the cannabis species best known now as marijuana. (Our article on the 1936 propaganda film “Reefer Madness” examines in greater detail why it’s called marijuana.)

Cannabis Indica (left) and Cannabis Sativa Photo de Kiffcowboy en Commons

Cannabis Indica (left) and Cannabis Sativa Photo de Kiffcowboy en Commons

Influence Over European Geopolitics

Hemp and the Catholic Church-Ireland Connection

Although hemp was present in Ireland at least as early as the seventh century from Viking ships (ropes, sails, etc.), it wasn’t actually cultivated there as a crop until the early 11th century. A study published in January 2023 on the origins of cannabis in Ireland explains that the onset of hemp cultivation correlated with the founding of British-Romano monasteries. In fact, the word for “hemp” in Irish, “cnáib,” is borrowed from clerical Latin’s “canapis” or “canapus,” according to that study. “Cnáib” first appeared in texts written in 1060, and Hemp Cooperative Ireland tells of an 1188 publication that mentions hemp cultivation in Limerick (southwest Ireland). The budding vine between the Catholic Church and the Irish people expanded (both positively and negatively) over the centuries and ultimately pitted both against Britain.

Irish Hemp in England’s Wars

Ireland’s hemp cultivation ramped up during British rule, from the late 1100s to the early 1900s. In the 1500s, King Henry VIII required – on penalty of heavy fines – Irish farmers to grow and harvest at least a quarter-acre of hemp to provide materials for the royal naval fleet. Once Queen Elizabeth took power over Ireland in 1558, she emphasized strengthening the royal navy in anticipation of an attack from her enemy, Catholic King Philip of Spain. Her concern – prophetically – was that King Philip would support fellow Catholics in Ireland and coordinate an attack on Anglican Protestant England.

To boost hemp production in Ireland, she removed customs taxes on hemp imported from there. Then, she began confiscating Irish wool products so that the Irish people would have no alternative textiles. Once farmers were forced to rely on hemp production and cultivated more of it for that reason, their hemp was taken and shipped to English factories to produce sails for ships. England had the largest navy in the world up to World War II, so the demand for ship parts was immense and continuous.

When the Irish did end up asking for and receiving help from King Philip, it led to the first Anglo-Spanish War (1587 to 1604). Throughout that, Ireland-grown hemp was facilitating the attack of Ireland’s enemy (England) on Ireland’s ally (Spain). The English armed forces defeated the Irish with scorched-earth policies that involved destroying homes, lands and entire families. A tenuous peace treaty was signed days after Queen Elizabeth’s death.

These ships consistently required large sails. Photo credit: Vallejo Gallery, Public Domain, wikimedia commons

These ships consistently required large sails. Photo credit: Vallejo Gallery, Public Domain, wikimedia commons

The Idea of Using Irish Hemp as Political Leverage

It wasn’t until the 1800s that someone in Ireland pointed out the powerful position Irish hemp farmers were in by virtue of how dependent England was on them for its military might. The English were even willing to sacrifice a primary fuel source, peat, by draining Ireland’s peat bogs to grow hemp there and meet the rising demand for sails. Even in peacetime, the English needed 14,000 tons of hemp a year from Ireland, so wartime demands for sails compounded that; they were desperate. The bog-drainage plan was dropped, though, once the royal navy’s hemp demand plateaued after Napoleon’s armies had receded.

However, the plan’s proposal made an unintended impression on colonized Ireland, and someone dared to dream of attaining Irish sovereignty via the island’s domestic hemp industry. That person was George Sigerson, a prominent scholar and physician, and a future senator in the (now-former) Irish Free State. In 1866, he published an argument for reaching that goal in the 32-page pamphlet “Cannabiculture in Ireland; its profit and possibility.”

His argument included a comprehensive instruction manual for using hemp cultivation to grow Ireland’s economy, distribute wealth and create sustainable jobs. With it, he called upon Irish farmers to mass-produce hemp as a means of economic empowerment during the height of English empire-building. Attesting to the plausibility of his idea, he cited hemp industry successes in several other countries, including Russia, the United States of America and even England.

Regrettably, Sigerson’s call to action received no response, and the idea languished. A deep-seated history of clan rivalries, explained here by Ask About Ireland, could provide insight into how progress relying on unification was culturally obstructed.

Hemp Rope Photo by Ji-Elle, CC BY-SA 3.0 via Wikimedia Commons

Hemp Rope Photo by Ji-Elle, CC BY-SA 3.0 via Wikimedia Commons

Influence Over Western Medicine

Cannabis Indica Goes to Europe

Although Europeans named the indica subspecies after discovering it in India, this subspecies had actually made its way into Europe via contact with people from the Middle East centuries before. As reports, indica rose in popularity as Islam spread during the ninth century. The Quran forbade alcohol and certain other intoxicating substances, but cannabis was not among those. As such, nomadic tribes across the Middle East and parts of Asia inhaled smoke from smoldering cannabis (which they called hashish) seeds and flowers to get high.

By the same rationale, Napoleon’s troops took up smoking cannabis indica when he forbade them to drink while they were fighting in Egypt. When they returned to France, they brought some indica back with them and smoked it there, but the habit remained local. Even so, knowledge of the plant found its way into medical circles, where people were surprised to find a familiar-looking plant that caused such effects. In 1785, French naturalist Jean-Baptiste Lamarck proposed that there were two cannabis species. It was he who created the name “indica.” He concluded that sativa was what had been cultivated in the West, and that indica was indigenous to India.

Photo by Deep Kuma/

Photo by Deep Kuma/

The Irish Medical Genius

Limerick-born William Brooke O’Shaughnessy brought indica to the forefront in Western medicine by studying it and documenting it in unprecedented detail. The use of psychedelics in Ireland for medicinal purposes goes back millennia, as we discuss in an article on ancient Druidic priests. However, the Druids didn’t employ the Scientific Method for posterity, whereas O’Shaughnessy did.

O’Shaughnessy made extraordinary achievements in chemistry, toxicology, ethnobotany, clinical medicine and even telegraphy, as documented in a 2017 book on botany and biotechnology. After departing Ireland, he studied in Edinburgh and received his medical degree at age 20. Then, he moved to London, where he continued to build a reputation, making a name as a prodigy of forensic chemistry and toxicology. His advances in treating cholera saved many lives, and he was highly celebrated.

In spite of those achievements, he was unable to obtain a practitioner’s medical license in London due to political obstructions as an outsider. Consequently, he accepted a position with the East India Company as an assistant surgeon. In India, he set numerous precedents, such as becoming the first chemistry professor of Calcutta Medical College and establishing the electric telegraph in India. By age 28, he published a chemistry manual that proved essential to advances in medicine. Two years after that, he delivered a lecture was later described as, according to the book previously mentioned, “the definitive account of cannabis of the early nineteenth century.”

The lecture was published under the title “Extract from a Memoir on the Preparations of the Indian Hemp, or Gunjah, (Cannabis Indica) their effects on the animal system in Health, and their utility in the Treatment of Tetanus and other Convulsive Diseases.” In it, he provided scientific proof that indica could be used to treat rheumatic diseases, tetanus, cholera and epilepsy. His comprehensive analyses were documented so thoroughly that his lecture even became the template for future research.

When he returned to England on sick leave in 1841, O’Shaughnessy brought a large supply of Calcutta cannabis indica with him. This prompted further studies, trials and applications of the plant, reviving and amplifying the West’s interest in medical cannabis. Over the years, his lectures and publications spread knowledge of medicinal cannabis throughout not only Europe but also Canada and the United States of America. To this day, according to the book mentioned previously, O’Shaughnessy is often remembered as the modern father of cannabis therapeutics.

Medical Cannabis owes a debt to the pioneering work of Irish Doctor William Brooke O’Shaughnessy. Image Credit:Olga Yastremska/

Medical Cannabis owes a debt to the pioneering work of Irish Doctor William Brooke O’Shaughnessy. Image Credit:Olga Yastremska/

The Legacy Cannabis Left on Ireland

From determining the strength of an empire’s naval fleet to renewing Western medical science’s interest in alternative health care, cannabis made quite an impact on the Irish nation and people. Although Medieval Irish farmers didn’t avail themselves of the wealth resident in hemp cultivation, they did possess that magnificent power. And although psychotropic medicines proceeded to be banned by Western governments, the initial breakthrough of medical cannabis in the West was revolutionary. (This paralleled what happened with psychedelic microdosing, as we explore here.) That’s a pretty impressive legacy.

Kathleen Hearons is a writer, editor, linguist and voice over actor from Los Angeles. She specializes in creative writing and research-intensive analysis and reporting.  






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