Queen Elizabeth II became the fourth longest-serving monarch in the world on Wednesday, after serving the British throne for 68 years and 34 days.

Queen Elizabeth II surpassed K'inich Janaab Pakal the Great, who became a king at the age of 12, and ruled the Maya city-state of Palenque for 68 years and 33 days before his death in 683AD. With the milestone, the British monarch has joined the likes of Thailand's King Bhumibol Adulyadej, who died in October 2016, and Johann II of Liechtenstein, who passed away in February 1929, reports Mail Online.

The world's longest-ever reigning monarch was Louis XIV of France, who acceded the throne at the mere age of four and remained king for 72 years and 110 days. If the British monarch continues to reign till May 27, 2024, she will replace Louis XIV as the longest-serving monarch in verifiable history.

The 93-year-old monarch already holds the title of the longest-living reigning monarch. Also, she officially became the longest-serving British monarch in September 2015, surpassing her great-great-grandmother Queen Victoria.

However, the British queen who has added several accolades and titles to her name wasn't initially supposed to ascend to the throne. She was the first child of the Duke and the Duchess of York- George VI and Elizabeth, and was third in the line of succession to the British throne at the time of her birth, behind her uncle Edward and her father.

When her grandfather died in 1936 and her uncle succeeded as King Edward VIII, she became second in line to the throne, after her father. However, reigning monarch was not expected to become queen as Edward was likely to marry and have children of his own who would precede her in the line of succession. But in a surprising twist of events, Edward abdicated the throne to marry divorced socialite Wallis Simpson, who wasn't approved by the prime minister of the UK and the Dominions.

After his abdication, the queen's father became King George VI and her mother became Queen Elizabeth- the Queen Mother, making her heir presumptive and second in line to the throne. However, if her parents had given birth to a son later, he would have been heir apparent and above her in the line of succession.

Queen Elizabeth II
Britain's Queen Elizabeth II has been troubled by a series of scandals and misfortunes in a year she described as "quite bumpy" in her Christmas Day message Photo: POOL / Paul Edwards

Nevertheless, she was proclaimed the queen on February 6, 1952, after her father's premature death, when she was 25-years-old. Her coronation took place at Westminster Abbey on June 2, 1953, and was the first ceremony to be televised.