Catherine Barton (1679-?) was Isaac Newton's half-niece, and had a relationship with Charles Montagu, 1st Earl of Halifax after his wife's death in 1698. An excerpt of an uncharacteristically warm letter from Newton survives, regarding her contraction of smallpox: "Pray let me know by your next how your [face is] and if your fevour be going. Perhaps warm milk from ye Cow may [help] to abate it. I am Your loving Unkle, Is. Newton." Sir Isaac Newton, PRS, (4 January [O.S. 25 December 1642] 1643 – 31 March [O.S. 20 March] 1727) was an English physicist, mathematician, astronomer, alchemist, inventor and natural philosopher who is generally regarded as one of the most influential scientists in history. ... Charles Montagu, 1st Earl of Halifax (April 16, 1661 - May 19, 1715) was Chancellor of the Exchequer, poet, statesman, and Earl of Halifax. ... Smallpox (also known by the Latin names Variola or Variola vera) is a highly contagious disease unique to humans. ...