The Islamic calendar takes as its starting point the Hijri, or the journey of the Prophet Mohammed and his followers from Makkah to Madinah, and consists of 12 lunar months and a year of either 354 or 355 days.
As a result, it moves 11 days each year in relation to the Gregorian calendar. To return to the same seasonal point as the Gregorian calendar takes 33 years.
Over four weeks, we are looking at the world as it was on previous occasions Ramadan happened during the month of May. It is a journey that takes us from the self-driving car to the horse and carriage, from the age of the internet to the age of empires.
This week we look at Ramadan 1339, from May 9 to June 7, 1921.
Nearly a century later, the decisions and events of 1921 continue to shape the world we live in today.
It was a time when much of the world wanted only to look forward, away from the carnage of the First World War that had ended only three years earlier.
That yearning for new ideas would transform the arts and music, but also lead millions embrace ideologies such as fascism and communism, and leaders whose promises would soon bring even worse conflict and the slaughter of tens of millions more.
For the Middle East, the year, and indeed the coming century, would be defined by 19 days in March. The Cairo Conference was a series of meetings called by the British after unrest in the new country of Iraq.
It was to look at the issues raised by the collapse of the Ottoman Empire and agree a common approach for the future.
Britain was represented by its new colonial secretary, Winston Churchill, and joined by T E Lawrence (of Arabia) and Gertrude Bell, both influential on policy in the region.
The talks were defined by two previous agreements – Sykes-Picot, which had secretly proposed carving up the Ottoman territories into spheres of French and British control, and the 1917 Balfour Declaration, in which Britain gave support to a homeland for the Jewish people.
The decisions made in Cairo were not revealed until late June, and then with little publicity. The new states of Lebanon and Syria would remain under French control and Britain would maintain a mandate over Palestine and continue to support a Jewish homeland.
Faisal bin Hussein, one of the leaders of the Arab Revolt, became king of Iraq and became known as King Faisal I.
His brother Abdullah became king of the territory east of the Jordan, then called Transjordan, establishing Hashemite rule that continues to this day.
In what is now Saudi Arabia, Hussein bin Ali, Sharif of Makkah and the father of King Faisal and King Abdullah, was recognised as king of the Hejaz, and Emir of Riyadh Abdul Aziz Ibn Faisal Al Saud, who would soon unite the country and become king of Saudi Arabia, was left with the Nejd central desert.
Earlier promises that the Arabs, once liberated from the Ottomans, would be free to rule themselves, were abandoned. Even Churchill called the conference: “A meeting of 40 thieves.”
The aftermath of Cairo was a hint of the troubles to come. Riots in Jaffa left 48 Arabs and 47 Jews dead.
These events had little effect in what is now the UAE. In Dubai, Sheikh Saeed Al Maktoum, the father of Sheikh Rashid, was Ruler of the emirate. The Ruler of Abu Dhabi was Sheikh Hamdan bin Zayed, son of Zayed the Great. In the following year, he would be succeeded by Sheikh Sultan, father of the first UAE President.
The West had several problems. Germany, humiliated by defeat in the First World War and suffering economic and social problems resulting from the Treaty of Versailles imposed by the victorious allies, looked for solutions in new political movements.
Some turned to communism, but others turned to a party created a year earlier, called the National Socialist German Workers Party – Nazis, for short. On July 29, the party elected a new leader, or fuhrer. His name was Adolf Hitler.
In Russia, the communist Bolshevik regime consolidated its grip on power after the Revolution of 1917. By the end of February, the Red Army had seized control of Georgia. The new Soviet government began to impose ideologically driven economic policies that, combined with a drought, led to the start of a year-long famine in the spring that would leave an estimated five million dead from starvation.
Both fascism and communism continued to spread across borders during 1921. Communist parties were established in China and Czechoslovakia, while the National Fascist Party was formed in Italy by Benito Mussolini in November, seizing power within a year. For the people of Ireland, 1921 was also a momentous year. The warfare between Irish Republicans and British government forces ended with a ceasefire agreement in July and a treaty to create the Irish Free State on December 6. Protestant Northern Ireland would become a province of the UK.
But 1921 was not all violence, division and extremist politics. This was the start of the Roaring Twenties, a decade in which the world embraced modernity, from music to motoring. Jazz music was growing in popularity, and in fashion, women’s hemlines were rising towards the knee, with more form-fitting styles.
Cinema became ever more popular as a form of mass entertainment, helped by the release of two hit films during the year. The Kid, starring Charlie Chaplin, opened in January, drawing on the actor's poverty-stricken childhood in London.
In October it was The Sheikh, a romance that took, for the time, an astonishing $1 million at the box office, and made a heartthrob of its star Rudolph Valentino.
In 1921 Albert Einstein was awarded the Nobel Prize for Physics, although not for his Theory of Relativity. Europe basked in a heatwave during which Breslau in Poland reached an unprecedented 38°C, while American audiences enjoyed a live radio broadcast of the baseball World Series for the first time.
In a play in London, the word "robot" was coined, with R.U.R. by Karel Capek and a plot about a factory that makes mechanical humans who then turn on their masters and all but wipe out the human race.
Notable deaths in 1921 included the composers Saint-Saens and Engelbert Humperdinck, Wild West hero Sheriff Bat Masterson, the opera singer Enrico Caruso and John Boyd Dunlop, inventor of the tyre that still carries his name.
Births included Nancy Reagan, the actors Charles Bronson and Carol Channing, the first American in space, John Glenn, and Tug Wilson, first commander of the Abu Dhabi Defence Force. Prince Philip, consort of Queen Elizabeth, born on Corfu on June 10, 1921, will shortly celebrate his 98th birthday.
The year was also the first in which the first portions of fast food were served up. On September 13, 1921, the first White Castle burger outlet opened in Wichita, Kansas.