The Prince of Wales and Duchess of Cornwall attended a memorial ceremony at the Belgrade New Cemetery as they began their visit to Serbia.
Charles and the president of Serbia, Tomislav Nikolic, laid wreaths at the Memorial Crypt of the Belgrade Defenders, followed by a moment of pause for reflection before Serbian priests read a short prayer.
To mark the occasion, the prince wore an RAF tie, Veterans badge and the shoes issued to him when he joined the RAF in March 1971.
Dressed in a grey and black Bruce Oldfield coat, the duchess stood and observed proceedings as the national anthems of both countries were played by a military band.
The memorial is located above an underground crypt in which the bodies of 4,603 known and unknown soldiers have been laid to rest.
Shortly after the event, Charles and President Nikolic attended a wreath-laying ceremony at the Commonwealth War Graves Cemetery.
They were led into the site by a piper from the Royal Irish Regiment, and greeted by a British Military band.
At the conclusion of the ceremony, Charles asked President Nikolic to pause for a short time so he could pay his respects. Following the wreath laying, the Last Post was played and a short prayer was said.
The cemetery was created to receive the remains of British and Commonwealth casualties brought in from more than 60 small burial grounds and from isolated sites all over the former Yugoslavia.
The burials in the War Cemetery include escaped prisoners of war from Italy and Greece.
The civilians buried there include a mining technician, an English teacher, a newspaper correspondent, a member of the Embassy staff and the child of another member of Embassy staff.
They were buried or re-buried in the cemetery with the permission of the Army Graves Service.
Crowds lined the streets as the royal couple made their way to the Kalemegdan Fortress. They walked towards the terrace where they took in the view of the confluence of the River Danube and the River Sava.
Camilla then left to make her way to an event at Zvecanska Children's Home where she was due to meet representatives of Unicef and the Djokovic Foundation.
Charles continued to walk in the sunshine towards the Roman Well, through the King's Gate, along the Sava River Promenade and up the Grand Staircases towards the Victor Monument.
He stopped briefly at the World War One - Belgrade in 1915 open-air exhibition before walking on to Princess Ljubica's residence.
The building is one of a few that survived the first reign of Prince Milos Obrenovic, and was built between 1829 and 1831. Members of the public excitedly hurried to get photos of the prince, some applauding as he passed by.
The prince was greeted at the residence by the Choir of the Jewish Community in Belgrade. He was then invited to take a seat in the Divan room to engage in an inter-faith dialogue with representatives from Serbia's Christian, Muslim and Jewish communities.
Present were His Holiness Patriarch Irinej Gavrilovic, the Serbian Patriarch, Archbishop Stanislav Hocevar, the Roman Catholic archbishop of the Archdiocese of Belgrade; Muhamed Jusufspahic, the Chief Serbian Mufti and Imam of Bayrakli Mosque in Belgrade.
Chief Rabbi Isak Asiel was representing the Jewish Community of Belgrade and Serbia, and Father Robin Fox Anglican Chaplain to St Mary's Belgrade.
Charles took to the streets again, this time to make a short journey to the Serbian Orthodox Patriarchate, where he had a short private meeting with Patriarch Irinej Gavrilovic.
Patriarchate is home to a chapel where Anglican Christmas services have been held since the 1920s. They gathered in the chapel, surrounded by candles, and had a short discussion while a choir sang in the background.