Gundulf's great Tower was used both as fortress and prison - Ralph Flambard, Bishop of Durham and favourite of Rufus, was imprisoned there by Henry I, escaping by a rope after a heavy drinking session that left his jailers sleeping.
Stephen took refuge there during troublesome times, keeping his Court within the walls at Whitsuntide of 1140. Longchamp, Bishop of Ely, held the Tower for absent Richard I against the men-at-arms of John. The new defences that were added served John well in his frequent retreats to the Tower.
In the time of Henry III, who spent much of his youth in the Tower and later filled it with prisoners, the Tower menagerie was inaugurated by three leopards, presented by the Emperor Frederick. Henry added an elephant and a white bear, the last being permitted to fish in the Thames.
Animals were also kept in the Lion Tower-sometimes providing lion and bear baiting entertainments - until the last were dispatched in the nineteenth century to Regent's Park. Edward II brought the first lion to the Tower, and for his food the keeper was allowed 6d. a day, although one penny fed a captive knight.
Edward I invited within the Tower of London the alchemist Raymond Lully, and in the "secret chamber of St. Katharine" Lully declared that he transformed crystal into diamond for the King's benefit. It was popularly believed that Edward's Crusades were financed by like wizardry, although the 600 Jews whom he committed to the vaults of the White Tower also contributed.
To the Tower Edward II sent Knights Templars found south of the Trent after the dissolution of the Order; in its frowning security his little daughter "Jane of the Tower" was born; there Queen Isabel and Lord Mortimer guarded Edward III during his minority ; and at the Tower, in 1330, Mortimer was executed.