King Charles confronted the monarch's rich and sometimes controversial past at the beginning of his visit to both Australia and Samoa.

On Sunday, October 20, Prince Charles and his wife, Queen Camilla, attended a religious event at St. Thomas' Anglican Church in Sydney, Australia. During the visit, the King signed the country's first official Bible and joint prayer book, according to the Daily Mail.

According to the magazine, the Bible is from the Reverend Richard Johnson, the country's first Christian pastor, and was reportedly signed by all members of the royal family who made the official visit.

According to the Daily Mail, Prince Charles “signed the Bible with his own fountain pen on the page below the late Princess Diana's signature.”

Prince Charles was married to Princess Diana from 1981 to 1996, but their divorce was finalized after years of separation and only a year before Diana's death in a tragic car accident.

In 1995, Princess Diana famously told the BBC: “There were three people in this marriage, so it was a bit crowded,” referring to the current queen.

According to the Daily Mail, the late Queen Elizabeth signed the same Bible in 1954 “on the incumbent monarch's first visit to the site. At the time, the Archbishop said the Bible “represents an important history of this church and state.”

The whirlwind royal visit was King Charles' first since his coronation and his most significant overseas trip since announcing in February that he had been diagnosed with an unspecified cancer.

As Marie Claire previously reported, the King has followed his doctors' advice and temporarily suspended chemotherapy during both his visits to Australia and Samoa, traveling instead with two doctors who will closely monitor him.

King Charles' return visit to Australia brings back memories of his visit in the 1980s with the late Princess Diana.

At the time, in 1983, Princess Diana was only 21 years old, had been married to then-Prince Charles for less than two years, and was relatively new to royal life with its constant spotlight.

“She looked anxious, even melancholy, and kept looking at the tarmac with a vacant stare throughout the brief photo shoot at the airport,” reported The Age at the time of the couple's first landing in Australia.

“Whatever the reason, Princess Diana had to work hard to make the proud and happy young mother smile for the photographers,” the media outlet added.