Prince Philip had a huge role in the murder mystery of the Romanovs in 1918. After years of investigation on the brutal death of the Russian imperial family, the Duke of Edinburgh stepped in to help unlock the mystery.

In 1918, all members of the Romanov family, Tsar Nicholas II, Tsarina Alexandra and their five children, including their three servants, were killed through a painful execution. Their executioners buried their remains in a secret location, and their bodies were not discovered until 1979. However, it was only in 1988 that the bodies were confirmed to belong to the Romanov family.

The mystery surrounding the murder of the family would not have been solved if not for Prince Philip, who gave a sample of his blood to help identify the recovered bodies in the unmarked graves. Prince Philip’s DNA was key in the investigation since Tsarina Alexandra is her grand-nephew.

According to Dr. Peter Gill, who was with the Forensic Science Service at that time, the cooperation of Prince Philip helped uncover the details surrounding the murders. “Blood samples from relatives, including His Royal Highness The Duke of Edinburgh, and advances in DNA profiling and 3D reconstruction, helped to positively identify the remains of the imperial family and enabled the investigation to reach convincing conclusions,” he said.

Gill explained that by using mitochondrial DNA, their team was able to prove that the bones found in the graves belonged to the Romanovs. They were grateful that when they invited Prince Philip to take part in the investigation, the duke willingly said yes.

Years after the identity of the bodies were confirmed, the research was put on display at the Science Museum in London. The exhibit now includes graphs of the tsar’s and tsarina’s blood and the details of Prince Philip’s blood. It shows the decades of work given into piecing together the exact details of what happened to the Romanovs and how Prince Philip helped solve the murder of his relatives.

Prince Philip is related to the Romanovs through the maternal line. Once, when asked about visiting Russia, he said he would love to. He said, however, that he’s also hesitant since “the bastards (Russians) murdered half my family.”

Prince Philip Prince Philip, Duke of Edinburgh (C), in his role as Captain General, Royal Marines, makes his final individual public engagement as he attends a parade to mark the finale of the 1664 Global Challenge. Hannah McKay - WPA Pool/Getty Images