The artist behind Prince Philip's final portrait reveals 3 hidden details in the painting - and what they mean

• Prince Philip's final portrait marked his retirement from public service in 2017.
• Ralph Heimans, the artist behind the portrait, revealed three subtle details hidden in the work.
• It shows a significant room and portrait for Philip's family, and a nod to the royal's Danish heritage.

In 2017, Prince Philip spent just one hour sitting for a final portrait before he retired from a lifelong career in public service.

On first look, the portrait by Australian-British royal painter Ralph Heimans simply depicts the late Duke of Edinburgh in formal attire standing in a long corridor at Windsor Castle. The duke looks regal yet slightly hunched in posture, surrounded by fine art and busts.

Upon closer inspection, however, the portrait is saturated with hidden references to Philip's family, history, and heritage, and subtle threads that form the fabric of the duke's unique life. According to Heimans, who previously painted Prince Charles and the Queen, these details were intentional - the result of a collaborative effort between himself and Philip.

Speaking to Insider, Heimans reminisced about the short time he spent with the duke, who he said came across as a man with a distinct personality.

"He has this charisma which is quite striking," he said. "His sharp wit, humor, and his forthright nature are all qualities you can imagine but when you meet him you really do get a flavor."

The corridor depicted in the painting leads to the room where Prince Philip's mother and grandmother were born

According to Heimans, the grand corridor is located in the private quarters of Windsor Castle that Philip shared with the Queen during their 73 years of marriage.

Aside from being their residential location, it has further emotional significance.

"At the end of that corridor was a room where his mother and his grandmother were born," Heimens said, referring to Princess Alice of Battenburg who gave birth to Philip in Corfu in 1921, and Alice's mother Princess Victoria of Hesse.

"It's also where he stays when he has lived at Windsor Castle," Heimans said, speaking of Philip. "And now it turns out that he has also passed away there."

"In some ways that that corridor itself represents his lifespan," the artist added. "There's something very powerful and symbolic about that space that I think has added to the strength and the poignancy of the portrait."

The portrait includes a painting of Queen Victoria with the Danish royal family, including Philip's mother as a young girl

At the forefront of the painting, hanging on the right-hand side is a group painting that depicts Queen Victoria and the Danish royal family, which includes Philip's mother, Alice, as a young girl.

Philip was the fifth child and only son of Prince Andrew of Greece and Denmark and Princess Alice, and his maternal grandmother, Princess Victoria of Hesse, was Queen Victoria's grandmother, which made him and Elizabeth II third cousins.

Philip sacrificed his European royal titles in order to marry Elizabeth and became the Duke of Edinburgh through King George VI's Letters Patent on November 19, 1947.

For Heimans, acknowledging the close links between British and Danish royalty before Philip and Elizabeth married adds "poetic resonance" to the corridor because their story "is all encapsulated within that one space."

"It's almost as though the light and shade that passes through that corridor or represent times of light and shade within his life," he said. "There's something sort of deeply resonant about the sense of perspective within the painting that represents his lifespan."

As The Times reported, Philip was vocal before his death about incorporating his roots into his funeral proceedings. This resulted in the flag laid on top of Philip's coffin featuring the Danish coat of arms and the Greek flag, Insider's George Arkley previously reported.

Philip's national identity was multifaceted; he was born a Greek prince with Danish heritage, then fled to France but was educated in Britain.

"If anything I've thought of myself as Scandinavian, particularly Danish. We spoke English at home. The others learned Greek. I could understand a certain amount of it. But then the conversation would go into French. Then it went into German, because we had German cousins," Philip was quoted saying in a 2014 profile on The Independent. "If you couldn't think of a word in one language, you tended to go off in another."

In his portrait, the duke wears Windsor attire and the Order of the Elephant, Denmark's highest-ranked honor

The Order of the Elephant is a Danish order of chivalry and is Denmark's highest-ranked honor, which dates back to the 15th century, according to the royal family of Denmark's website. It is now solely used to recognize royals and heads of state.

Heimans' painting was commissioned in partnership with the Danish National History Museum so it was a conscious decision to pay tribute to Philip's Danish heritage in the portrait.

"In terms of what he would wear, I suggested a Windsor attire with the Order of the Elephant, which is the Danish highest order to say something about his origin, which they were very happy with," Heimans said.

The elephant ornament can be seen hanging from Philip's blue sash as his positioning implies that he is walking away - a conscious sense of finality, according to the artist.

"I wanted to convey that sense of farewell," he said. "If you're standing in that corridor it's as though he's glancing at the viewer and you can imagine if it was cinematic, that the next scene would be him walking away down that corridor."