Below is an account of this relationship.

The first written medicinal use of cannabis goes back to 2727BC

Cannabis seeds used for food in China.

4000BC Textiles made of hemp are used in China.

2727BC First written record of cannabis use as medicine in China.

1500BC Scythians cultivate cannabis and use it to weave fine hemp cloth.

1200 - 800BC Bhang (dried cannabis leaves, seeds and stems) is mentioned in the Hindu sacred text Atharva veda (Science of Charms) as "Sacred Grass", one of the five sacred plants of India. It is used medicinally and ritually as an offering to Shiva.

700 - 600BC The Zoroastrian Zend-Avesta, an ancient Persian religious text of several hundred volumes, and said to have been written by Zarathustra (Zoroaster), refers to bhang as Zoroaster's "good narcotic".

700 - 300BC Scythian tribes leave cannabis seeds as offerings in royal tombs.

500BC Scythian couple die and are buried with two small tents covering censers. Attached to one tent stick was a decorated leather pouch containing wild cannabis seeds.

This closely matches the stories told by Herodotus. The gravesite, discovered in the late 1940s, was in Pazryk, northwest of the Tien Shan Mountains in modern-day Kazakhstan.

500BC Hemp is introduced into northern Europe by the Scythians. An urn containing leaves and seeds of the cannabis plant, unearthed near Berlin, is dated to about this time.

500 - 100BC Hemp spreads throughout northern Europe.

430BC Herodotus reports on both ritual and recreation use of cannabis by the Scythians.

100 - 0BC The psychotropic properties of cannabis are mentioned in the newly compiled herbal Pen Ts'ao Ching which is attributed to an emperor circa 2700BC.

AD0 - AD100 Construction of Samartian gold and glass paste stash box for storing hashish, coriander, or salt, buried in Siberian tomb.

AD70 Dioscorides mentions the use of cannabis as a Roman medicament.

AD170 Galen (Roman) alludes to the psychoactivity of cannabis seed confections.

AD500 - 600 The Jewish Talmud mentions the euphoriant properties of cannabis. (Abel 1980)

AD900 - 1000 Islamic Scholars debate the pros and cons of eating hashish. Use spreads throughout Arabia.

1090 - 1256 In Khorasan, Persia, Hasan ibn al-Sabbah, the Old Man of the Mountain, recruits followers to commit assassinations. Legends develop around their supposed use of hashish.

These legends are some of the earliest written tales of the discovery of the inebriating powers of cannabis and the supposed use of hashish.

Early 12th Century Hashish smoking very popular throughout the Middle East.

12th Century Cannabis is introduced in Egypt during the reign of the Ayyubid dynasty on the occasion of the flooding of Egypt by mystic devotees coming from Syria.

1155 - 1221 Persian legend of the Sufi master Sheik Haidar's of Khorasan's personal discovery of cannabis and it's subsequent spread to Iraq, Bahrain, Egypt and Syria. Another of the earliest written narratives of the use of cannabis as an inebriant.

13th Century The oldest monograph on hashish, Zahr al-'arish fi tahrim al-hashish, was written. It has since been lost.

13th Century Ibn al-Baytar of Spain provides a description of psychoactive cannabis.

13th Century Arab traders bring cannabis to the Mozambique coast of Africa.

1231 Hashish introduced to Iraq in the reign of Caliph Mustansir. (Rosenthal 1971)

AD1271 - 1295 Journeys of Marco Polo in which he gives second-hand reports of the story of Hasan ibn al-Sabbah and his "assassins" using hashish. First time reports of cannabis have been brought to the attention of Medieval Europe.

1378 Ottoman Emir Soudoun Scheikhouni issues one of the first edicts against the eating of hashish.

1526 Babur, first emperor and founder of Mughal Empire learned of hashish in Afghanistan.

1549 Angolan slaves brought cannabis with them to the sugar plantations of northeastern Brazil. They were permitted to plant their cannabis between rows of cane, and to smoke it between harvests.

Mid-16th Century The epic poem, Benk u Bode, by the poet Mohammed Ebn Soleiman Foruli of Baghdad, deals allegorically with a dialectical battle between wine and hashish.

17th Century Use of hashish, alcohol, and opium spreads among the population of occupied Constantinople.

1606 -1632 French and British cultivate cannabis for hemp at their New World colonies in Port Royal (1606), Virginia (1611), and Plymouth (1632).

Late 17th Century Hashish becomes a major trade item between Central Asia and South Asia.

Napoleon prohibited the use of cannabis in 1798

In the Americas, the Virginia Assembly passed legislation requiring every farmer to grow hemp. Hemp was allowed to be exchanged as legal tender in Pennsylvania, Virginia, and Maryland.

1753 It is formally christened Cannabis sativa in 1753 by Carl Linnaeus, although the debate on the correct classification of the varieties still rages today.

1793 The British impose regulation and begin collecting taxes on all forms of cannabis in India.

1794 Hemp becomes one of the most important agricultural products in the US. George Washington declares "make the most you can of the Indian Hemp seed and sow it everywhere."

1798 Napoleon discovers that much of the Egyptian lower class habitually uses hashish. He declares a total prohibition. Soldiers returning to France bring the tradition with them.

1800 Cannabis resin or charas is restricted in India.

1824 Restriction on charas is rescinded "as this drug was found on examination to be not more prejudicial to health than ganja or other intoxicating drugs" .

1840 In America, medicinal preparations with a cannabis base are available. Hashish is available in Persian pharmacies.

Le Club des Hachichins, or Hashish Eater's Club is established in Paris.

1856 British government tax cannabis trade in India.

1890 Queen Victoria is prescribed cannabis for period pains. Her personal doctor claims: "It is one of the most valuable medicines we possess."

1894 After sitting for two years the British government's Indian Hemp Commission produces a 3,281 page report that concludes "...for the vast majority of consumers, the Commission consider that the evidence shows the moderate use of ganja or charas not to be appreciably harmful..."

1901 Royal Commission concludes that cannabis is relatively harmless and not worth prohibiting.

1906 Pure Food and Drug Act is passed, regulating the labelling of products containing alcohol, opiates, cocaine, and cannabis, among others. The law went into effect January 1, 1907.

1910 After the Mexican Revolution of 1910, Mexican immigrants flooded into the US, introducing to American culture the recreational use of marijuana.

The drug became associated with the immigrants, and the fear and prejudice about the Spanish-speaking newcomers became associated with marijuana. Anti-drug campaigners warned against the encroaching "marijuana menace," and terrible crimes were attributed to marijuana and the Mexicans who used it.

1915 - 1927 Cannabis begins to be prohibited for non-medical use in the US, especially in South West states.

1916 South African mine workers were encouraged to smoke because "after a smoke the native work hard and show very little fatigue". The usual mine practice was to allow three smokes resembling coffee brakes a day.

1916 - 1937 William Randolph Hearst's newspapers introduced the word 'marijuana' into English from Mexican slang.

Hearst sold lots of newspapers using stories about "coloured" men using drugs to corrupt white women. Many of them allegedly carried big knives and would go wild at any provocation. New techniques for processing hemp for paper that pose a serious threat to his timber based paper businesses provide the motivation.

1925 Britain signed the 1925 Geneva International Convention on Narcotics Control, organised by the League of Nations. Cannabis is added to the list after Egypt and Turkey request it.

1928 Recreational use of cannabis is banned in Britain when the Dangerous Drugs Act is passed.

1930 During the Great Depression, massive unemployment increased public resentment and fear of Mexican immigrants, escalating public and governmental concern about the problem of marijuana.

This instigated a flurry of research which linked the use of marijuana with violence, crime and other socially deviant behaviours, primarily committed by "racially inferior" or underclass communities. By 1931, 29 states had outlawed marijuana as calls to action against drug crazed Mexican and African Americans prove a big vote winner.

1935 Chinese government moves to end all cannabis cultivation.

1936 Propaganda film "Reefer Madness" is made to scare American youth away from using cannabis. The movie remains a cult classic.

1937 Cannabis made federally illegal in the US with the passage of the Marihuana Tax Act.

The act is pushed through by former Prohibition Commissioner Harry J Anslinger, now head of the Federal Bureau of Narcotics. The American Medical Association and the Oil Seed Institute opposed the law, but were ignored. Anslinger quoted press cuttings as proof that cannabis was "the most violence-creating drug on this planet".

Anslinger used the new law to expand his Bureau. He began an ugly campaign against "demon dope" using films and posters, associating it with jazz "voodoo music", inter-racial sex, madness and death.

1940s During World War II, imports of hemp and other materials crucial for producing marine ropes, parachutes, and other military necessities became scarce.

In response, the US Department of Agriculture launched its "Hemp for Victory" program, encouraging farmers to plant hemp by giving out seeds and granting draft deferments to those who would stay home and grow hemp. By 1943, American farmers registered in the program harvested 375,000 acres of hemp.

1944 LaGuardia Report by the New York Academy of Medicine issued an extensively researched report declaring that, "contrary to earlier research and popular belief, use of marijuana did not induce violence, insanity or sex crimes, or lead to addiction or other drug use."

1950 For the first time ever in the UK there were more prosecutions for cannabis than for opium and manufactured drugs put together, 86 for cannabis, 41 for opium and 42 for others. That year a series of police raids on jazz clubs produced a fresh crop of British news stories about black men with drugs and white women.

1960s A changing political and cultural climate was reflected in more lenient attitudes towards cannabis.

Use of the drug became widespread in the white, upper-middle classes in the West. Reports commissioned by Presidents Kennedy and Johnson found that cannabis use did not induce violence nor lead to use of heavier drugs. Policy towards marijuana began to involve considerations of treatment as well as criminal penalties.

1961 A new treaty was organised, the United Nations Single Convention on Narcotics Drugs. It updated all previous drugs treaties, and set up classifications of drugs according to their supposed harmfulness.

Cannabis went into the same list as the opiates and cocaine, "having strong addictive properties" and/or "'a risk to public health." Only medical or scientific uses were permitted, and the World Health Organisation, advised by Anslinger, considered cannabis to have no modern medical value.

Traditional and non-drug uses were to be closely controlled by governments. It was resolved that "use of cannabis is to be discontinued within 25 years".

1964 The first year when more white people than black were convicted of cannabis related offences in the UK. The total number of convictions, 544, was a little lower than in the previous two years.

1965 The 1965 Dangerous Drugs Act began to bring UK law in line with parts of the UN Single Convention. A new crime was created, allowing premises to be used for drug taking. Convictions for cannabis offences rose by 79% in a year.

1966 The Moroccan government attempts to purge cannabis growers from Rif Mountains fail.

1968 The UK government committee headed by Baroness Wootton concludes that "the long-term consumption of cannabis in moderation has no harmful effects".

1969 The UN estimates that there are between 200,000,000 and 250,000,000 cannabis users in the world.

Early 1970s Afghani hashish varieties introduced to North America for sinsemilla production. Westerners bring metal sieve cloths to Afghanistan. Law enforcement efforts against hashish begin in Afghanistan.

1970s Cannabis cultivated on a broad scale in Afghanistan.

1971 Under the Misuse of Drugs Act 1971, cannabis is classified as a class B drug in the UK. It becomes illegal to grow, produce, possess, or supply the drug.

The 1971 Act did not prohibit fibre from stalks, or seeds, and allowed medical and research uses, but all of them needed licences from the Home Office which for many years were issued to only a few official researchers.

Cannabis became decriminalised in the Netherlands in 1976

The bipartisan Shafer Commission, appointed by President Nixon at the direction of Congress, considered laws regarding marijuana and determined that personal use of marijuana should be decriminalized.

Nixon rejected the recommendation, but over the course of the 1970s, 11 states decriminalized marijuana and most others reduced their penalties.

1970 - 1973 Huge fields of cannabis cultivated for high quality hashish production in Afghanistan.

1975 America establishes the Compassionate Use programme for medical use of marijuana.

1976 Cannabis is decriminalised in the Netherlands.

1976 In the US a nationwide movement emerged of conservative parents' groups lobbying for stricter regulation of marijuana and the prevention of drug use by teenagers.

Some of these groups became quite powerful and, with the support of the DEA and the National Institute on Drug Abuse (NIDA), were instrumental in affecting public attitudes which led to the 1980s "war on drugs".

Clinton admitted smoking cannabis in his youth, but "did not inhale"

The UK Advisory Council proposed moving cannabis to class C under the Misuse of Drugs Act, and changing penalties for possession.

1981 The new Conservative government said that they had no intention of ever reducing penalties for drugs offences, still less of legalising or decriminalising cannabis.

1988 In the US, Drug Enforcement Administration (DEA) administrative law Judge Francis Young finds after thorough hearings that marijuana has clearly established medical use and should be reclassified as a prescriptive drug. His recommendation is ignored.

1992 US President Bill Clinton admits to having smoked cannabis in his youth, but claims that he never inhaled.

1993 An European Economic Community (EEC) directive made it possible for a few hemp farms to grow cannabis with very low THC content under licence.

1994 Over 72,000 people were convicted or cautioned in the UK for cannabis offences.

1996 California voters passed Proposition 215 allowing for the sale and medical use of marijuana for patients with Aids, cancer, and other serious and painful diseases. This law stands in tension with federal laws prohibiting possession of marijuana.

1997 Alliance for Cannabis Therapeutics (ACT) launches a major advertising campaign in the national press for the legalisation of marijuana for medical use.

1997 William Straw, son of UK Home Secretary Jack Straw, is cautioned by the police for allegedly selling cannabis, after being setup by a Daily Mirror journalist.

2000 Tony Blair agrees that cannabis should be legalised for medical purposes.

2000 Police Foundation Report suggests that certain drugs be reclassified and penalties reduced. The government rejects the recommendations.

2000 Peter Ainsworth, Francis Maude, Lord Strathclyde Bernard Jenkin, David Willets, Archie Norman and Oliver Letwin all members of the Conservative shadow cabinet admit smoking cannabis in the past.

2003 Canada is first country in the world to offer medical marijuana to its patients.

2004 Cannabis was reclassified from a Class B to a Class C drug in January. Possession remains illegal, but is not an arrestable offence.

2005 Sativex, the world's first cannabis derived medicine is licensed for use in Canada. The drug is developed by British Company GW Pharmaceuticals. The UK considers licensing Sativex as well.

2005 Advisory Council on the Misuse of Drugs asked to re-examine scientific evidence linking cannabis use in at risk adolescents and mental health problems.

2005 US Supreme Court rules that medicinal cannabis users in states that have legalised medicinal cannabis can still be prosecuted under federal laws.