Britain ended the practice of Suttee (burning widows on their husband’s pyre) in India. The British were told it was the custom. The British built gallows and explained that they also had customs. The local custom changed.
The same event came to mind for me. The full story is thus:
General Sir Charles James Napier, GCB (10 August 1782 – 29 August 1853), was a general of the British Empire and the British Army’s Commander-in-Chief in India.
A story for which Napier is often noted involved Hindu priests complaining to him about the prohibition of Sati by British authorities. This was the custom of burning a widow alive on the funeral pyre of her husband. As first recounted by his brother William, he replied:
“Be it so. This burning of widows is your custom; prepare the funeral pile. But my nation has also a custom. When men burn women alive we hang them, and confiscate all their property. My carpenters shall therefore erect gibbets on which to hang all concerned when the widow is consumed. Let us all act according to national customs.”