Sir, - Fintan O’Toole’s fascinating account of William Johnson reminds us that Irish history is often hiding in plain sight, scattered across other people’s national stories (“Irish-Mohawk chief at centre of great what-if in US history”, Opinion, July 7th).If readers enjoyed discovering an Irish-Mohawk family at the heart of the American Revolution, they might also look east to China, where a Co Armagh man is largely forgotten at home. Robert Hart, born in Portadown, spent almost half a century building and running the Qing Empire’s Imperial Maritime Customs Service. He helped modernise China’s customs administration, postal system and lighthouse network, advised emperors and diplomats, and became one of the most influential foreigners to serve China. Yet, unlike Johnson, he is scarcely known in the country that produced him.It is, perhaps, the fate of many Irish emigrants: their greatest achievements woven into other nations’ histories while quietly slipping from our own memory.O’Toole’s article is a welcome reminder that some of the most extraordinary chapters of Irish history were written far from Ireland itself. - Yours, etc,ENDA CULLEN,Co Armagh.