Colonel Altamont, the Nawaub of Lucknow’s prime favourite, an extraordinary man, who had, it was said, embraced Mahometanism, and undergone a thousand wild and perilous adventures was at present in this country, trying to negotiate with the Begum Clavering, the sale of the Nawaub’s celebrated nose-ring diamond, ‘the light of the Dewan.’
Source: wiktionary