The amphibious assault started at dawn on April 25, 1915, as wave after wave of British and Irish, French, Australian, New Zealand and Indian troops attacked heavily defended beaches, through barbed wire, and raced up cliffs through scrub.
Many were cut down before they reached the shore and the sea turned red from the blood.
Although Gallipoli is synonymous with Australian and New Zealand heroism, three times as many British and Irish troops were killed as Anzacs.
Some descendants feel the British involvement has been overlooked by history, perhaps because it ended in failure.
The royal party met 15 descendants of veterans who were selected to join the commemorations on the beautiful peninsula and ceremonies at Commonwealth War Graves Commission sites.
Ben Goddard, 37, was there to honour his great-grandfather Private Alfred William Goddard, of 2nd Hampshire Regiment, who landed on V Beach on April 25 1915.
He was hit on the elbow by shrapnel 11 days later but survived the hostilities and was discharged in 1918.
Mr Goddard, from Ropley, Hampshire, knew nothing about the Gallipoli Campaign until he researched his family tree and found out about his ancestor's war record.
"So many men fought and did not come back. That should be remembered, whether the campaign was a disaster or not," he said.
"I am really proud and honoured to have been chosen, representing the Hampshire Regiment, and be there for the people who did not come back."
- AAP
