India, March 12 -- Two museum visitors stroll past the display, not pausing by the dagger. Yet this object, on permanent exhibition at the Humayun World Heritage Site Museum in central Delhi, has acquired renewed fascination in light of the events unfolding in Iran.

Like India, Iran's long past has been moulded by the rise and fall of many empires. The dynasty that shaped the Iran we recognise today was the Safavid dynasty, founded by Shah Ismail I about 500 years ago. It was Ismail's son, Tahmasp I, who went on to become the longest-reigning Shah of Islamic Iran, solidifying the empire during his 50-year reign. A personal souvenir of that ruler rests in Delhi: the aforementioned dagger.

The weapon is simultaneously tied to the eventful...