A ceremony at India Gate will be an opportunity to honour a sacrifice that was in the past overlooked in both Britain and India.
The 70,000 Indian soldiers who fought and died for the British during World War One were once viewed in India as part of its difficult colonial history.
In a day devoted to paying tribute, William and Kate will also, quite literally, retrace Mahatma Gandhi's final footsteps before he was murdered.
The country's founding father - who once declared that non-violence, was a weapon for the brave - had a vision, which wasn't realised, of an independent, united land.
It was Prince William's relative, Louis Mountbatten - the last Viceroy - who oversaw the creation of India and Pakistan.
Prince William, with his wife, will end the day by speaking about his grandmother - a woman soon to turn 90, who's Britain's longest reigning monarch but who was never Queen Empress of India.
The Duke and Duchess of Cambridge's first official visit to India moves on to New Delhi.