| 241 | John Bohun of Midhurst (-) |
| 242 | John Cherleton (-), Lord Cherleton |
| 243 | John Cornwall (-10/11 December 1443), Baron of Fanhope |
| 244 | John de Holand (after 1358-9/10 January 1400), Duke of Exeter, parents: Thomas de Holand of Broughton and Joan of Kent "the Fair Maid of Kent" |
| 245 | John de la Pole (27 September 1442-1491/92), Duke of Suffolk |
| 246 | John de Mowbray (29 November 1310-1361), Lord Mowbray |
| 247 | John Dudley (-), Duke of Northumberland |
| 248 | John Golafre of Langley (-) |
| 249 | John Hastings (11 November 1372-30/31 December 1389), Earl of Pembroke |
| 250 | John Hastings (29 August 1347-1375) |
| 251 | John Neville (-), Lord Latimer |
| 252 | John of England (December probably 1250-31 August probably 1252), parents: Henry III and Eleonore de Provence |
| 253 | John of England (10 July 1266-before 8 August 1271), parents: Edward I “Longshanks” and Leonor de Castilla |
| 254 | John of Gaunt (1340-3/4 February 1399), Duke of Lancaster, parents: Edward III and Philippa de Hainaut |
| 255 | John of Gloucester (1470-November 1499), Captain of Calais, parents: Richard III |
| 256 | John of Lancaster (before May 1286-before 1327), Seigneur de Beaufort et de Nogent-Lartauld, parents: Edmund “Crouchback” of England and Blanche d'Artois |
| 257 | John of Lancaster (1362 or 1364-young), parents: John of Gaunt and Blanche of Lancaster |
| 258 | John of Lancaster (before 4 May 1366-young), parents: John of Gaunt and Blanche of Lancaster |
| 259 | John of Somerset (-after 1453), parents: John Beaufort |
| 260 | John of York (7 November 1448-young), parents: Richard of York and Cecily Neville |
| 261 | John Welles (-9 February 1499), Viscount Welles, parents: Lionel de Welles and Margaret de Beauchamp |
| 262 | John “of Gaunt” (probably November 1375-), parents: John of Gaunt and Constanza de Castilla |
| 263 | Juana I (14 January 1273-31 March or 2 April 1305), Queen of Navarre, parents: Enrique I and Blanche d'Artois |
| 264 | Julita (-29 January), parents: Henry II |
| 265 | Katharine de Roët (around 1350-10 May 1403), parents: Payn de Roët |
| 266 | Katherine Fillol (-) |
| 267 | Katherine Grey (August 1540-27 January 1568), parents: Henry Grey and Frances Brandon |
| 268 | Katherine of England (25 November 1253-May 1257), parents: Henry III and Eleonore de Provence |
| 269 | Katherine of England (around 1261/64-5 September 1264), parents: Edward I “Longshanks” and Leonor de Castilla |
| 270 | Katherine of Lancaster (1372/73-2 June 1418), parents: John of Gaunt and Constanza de Castilla |