sentences:  Kerr was born before 1682, the third son of Robert Ker, 3rd Earl of Roxburghe, and his wife Lady Margaret Hay, daughter of John Hay, 1st Marquess of Tweeddale.In 1704 and 1705 he travelled abroad in Holland, Switzerland, Italy, Germany and Austria.He served with reputation on the Continent under John Churchill, 1st Duke of Marlborough.