1 Thomas Osborne, the future lord treasurer, succeeded to the baronetcy and estates in Yorkshire on his father's death in 1647, and after unsuccessfully courting his cousin Dorothy Osborne, married Lady Bridget Bertie, daughter of the earl of Lindsey.
After a period of work in Holland he betook himself to England, where his treatise on lettres de cachet had been much admired, being translated into English in 1787, and where he was soon admitted into the best Whig literary and political society of London, through his old schoolfellow Gilbert Elliot, who had now inherited his father's baronetcy and estates, and become a leading Whig member of parliament.
Lord Palmerston offered him a baronetcy and a seat in the privy council, and the emperor of the French would gladly have conferred upon him some distinguished mark of his favour.
In 1873 he was offered a baronetcy by Gladstone, and again by Disraeli in 1874; in each case the honour was gracefully declined.
He was educated at Eton and Trinity College, Dublin, and in 1868 succeeded to the baronetcy on the death of his father.