They lived mainly at York Cottage, a relatively small house in Sandringham, Norfolk, where their way of life mirrored that of a comfortable middle-class family rather than royalty. George preferred a simple, almost quiet, life, in marked contrast to the lively social life pursued by his father. His official biographer, Harold Nicolson, later despaired of George's time as Duke of York, writing: "He may be all right as a young midshipman and a wise old king, but when he was Duke of York ... he did nothing at all but kill ["i.e." shoot] animals and stick in stamps." George was an avid stamp collector, which Nicolson disparaged, but George played a large role in building the Royal Philatelic Collection into the most comprehensive collection of United Kingdom and Commonwealth stamps in the world, in some cases setting record purchase prices for items.