Disraeli's siblings were Sarah (1802–1859), Naphtali (born and died 1807), Ralph (1809–1898), and James ("Jem") (1813–1868). He was close to his sister, and on affectionate but more distant terms with his surviving brothers. Details of his schooling are sketchy. From the age of about six he was a day boy at a dame school in Islington that one of his biographers later described as "for those days a very high-class establishment". Two years later or so—the exact date has not been ascertained—he was sent as a boarder to Rev John Potticary's St Piran's school at Blackheath. While he was there events at the family home changed the course of Disraeli's education and of his whole life: his father renounced Judaism and had the four children baptised into the Church of England in July and August 1817.