The Union flag flew as Sinn Fein took part for the first time in a wreath-laying ceremony to commemorate those British soldiers who died at the Battle of Messines.
During the ceremony, Assembly Speaker Mitchel McLaughlin and Derry Mayor Elisha McCallion, both of Sinn Fein, paid tribute to the Ulster Volunteer (UVF) “soldiers” who died in the First World War offensive.
Laden with symbolism, a colour party carrying the Union flag and other Commonwealth flags were accompanied by a band to the War Memorial in the Diamond.
After the Last Post was sounded, Mr McLaughlin and Ms McCallion lined up with former service personnel in front of the monument where they laid laurel wreaths, as others laid traditional poppy wreaths.
Afterwards, the standards were raised and a piper played a short lament before the colour party made its way back to London Street.
This is the 14th year of the commemoration, and the first time Sinn Fein has participated.
“It would be a tragedy if 100 years on we could not commemorate such events” said Mr McLaughlin.
“People from both traditions went off to fight side by side.”
Ms McCallion said she was fulfilling a commitment she made at the start of her term of office.
She said: “I said I would represent the entire city and district and an event like this shows that all traditions in the city can be treated with respect and dignity.”
Strategically the battle was seen as a success for the British and their allies. In later years former German commanders described it as crucial in the overall course of the war.