41. In the north-east corner stands a donjon , a high, square tower. 42. The donjon was at the centre of this change in castle architecture in the 12th century. 43. This castle was first established in 1286 as a wooden donjon but was rebuilt in stone. 44. On 24 July 1680, a terrible thunderstorm hit Heusden, and lightning struck the donjon . 45. A ruined mediaeval donjon was preserved. 46. Becoming known as Athlone Castle, this 12-sided donjon dates from the 13th century. 47. The central keep or Donjon was built in local brown stone in the 14th-century. 48. Upper floors can be reached through stairs running along the walls inside and outside the donjon . 49. Only twelve castles have a " donjon " that is considered " original ". 50. Though on intimate terms with the young Longueville to the donjon at the ch�teau de Vincennes.
