* Mehmed Çelebi, Governor of Anatolia ( Amasya ) and later as Ottoman Sultan Mehmed I Çelebi, ( 1389 – 1421 )-son of Devlet Hatun

* 1421 – 1459: Stephan Bodecker

113 Issue 5, pp 1404 – 1421

* 1421 – King Henry VI of England ( d. 1471 )

* 1450 – Agnès Sorel, mistress of King Charles VII of France ( b. 1421 )

* 1398 – 1421: Abou Saïd Othman ben Ahmed

* 1421 – Mehmed I, Ottoman Sultan ( b. 1389 )

Mehmed I Çelebi ( Ottoman: چلبی محمد, Mehmed I or Mehmed Çelebi ) ( 1390, Bursa – May 26, 1421, Edirne, Ottoman Empire ) was a Sultan of the Ottoman Empire ( Rûm ) from 1413 to 1421.

* 1461 – Henry Percy, 3rd Earl of Northumberland, English politician ( b. 1421 )

* 1421 – A seawall at the Zuiderzee dike in the Netherlands breaks, flooding 72 villages and killing about 10, 000 people.

* May 21 – King Henry VI of England ( murdered in prison ) ( b. 1421 )

* September 29 – Thomas of Lancaster, 1st Duke of Clarence, second son of Henry IV of England ( d. 1421 )

* September 23 – Charles of Viana, King of Navarre ( b. 1421 )

* Agnès Sorel ( 1421 – 1450 ): mistress to King Charles VII of France, first official royal mistress in France

* September 1 – Sōgi, Buddhist priest and Japanese poet ( b. 1421 )

## married in 1446 Princess Catherine of Saxony ( 1421 – 1476 )

On 11 June 1441, Frederick II married Catherine of Saxony ( 1421 – August 23, 1476 ), a daughter of Elector Frederick I of Saxony and Katharina of Brunswick-Lüneburg.

* February 9 – Agnès Sorel, mistress of Charles VII of France ( b. 1421 )

* August 28 – Jean Le Maingre, marshal of France ( d. 1421 )

Manuel also regained from Ottomans Nesebar ( 1403 – 1453 ), Varna ( 1403 – 1415 ), and the Marmara coast from Scutari to Nicomedia between 1403 – 1421.

Manuel II stood on friendly terms with the victor in the Ottoman civil war, Mehmed I ( 1402 – 1421 ), but his attempts to meddle in the next contested succession led to a new assault on Constantinople by Murad II ( 1421 – 1451 ) in 1422.

** Thomas of Lancaster, 1st Duke of Clarence, second son of Henry IV of England ( d. 1421 )

* Thomas of Lancaster, 1st Duke of Clarence ( 1388 – 1421 )

* Thomas Parker, or Pakare ( 1389 – 1421 ).

* Thomas, Duke of Clarence ( 1387 – 1421 )

In 1421 he accompanied the King's younger brother Thomas of Lancaster, 1st Duke of Clarence to the fighting in Anjou.

* Thomas of Lancaster, 1st Duke of Clarence ( 1388 – 1421 ), second son of Henry IV Bolingbroke, died without male issue

* Thomas of Lancaster, 1st Duke of Clarence 1399 – 1421

* Thomas Montagu, 4th Earl of Salisbury ( 1388 – 1428 ) ( restored 1421, although styled and summoned to parliament as such from at least 1409 )

The heir of Thomas de Camoys ( d. 1372 ) was his nephew, another Thomas de Camoys ( d. 1421 ), who was the grandson of Ralph de Camoys ( d. 1336 ) by his second wife, Elizabeth le Despenser, and the son of Sir John Camoys by his second wife, Elizabeth le Latimer, daughter of William le Latimer, 3rd Lord Latimer.

From 20 August 1383 to 26 February 1421 Thomas de Camoys ( d. 1421 ) was summoned to Parliament by writ, by which he is held to have become 1st Baron Camoys of the second creation.

Thomas de Camoys ( d. 1421 ) was twice married, firstly to Elizabeth Louches, the daughter of William Louches of great Milton and Chiselhampton, and secondly to Elizabeth Mortimer, daughter of Edmund Mortimer, 3rd Earl of March, and widow of Henry ' Hotspur ' Percy.

Thomas de la Warre refounded the church as a collegiate church in 1421.

* Thomas of Lancaster, 1st Duke of Clarence ( 1387 – 1421 ), second son of Henry IV Bolingbroke, was created Earl of Aumale along with his dukedom of Clarence, and carried both titles until his death without issue.

In 1421 the rector of the parish church, Thomas de la Warre ( Lord of the manor of Manchester ), obtained a licence from Henry V to refound the church as a collegiate foundation.

* 1406 – 1421 Thomas More

In 1421, Thomas de la Warre obtained a licence from King Henry V and from Pope Martin V to establish a collegiate foundation in Manchester, appropriating the parish church for the purpose.

* Sir Thomas Dutton ( 1421 – 1459 ), British knight

In 1421 the ownership of the Castle reverted to Sir Ralph Lumley's grandson, Thomas.

* Thomas FitzGerald, 7th Earl of Kildare ( c. 1421 – 1477 ), Lord Chancellor of Ireland

Thomas of Lancaster, 1st Duke of Clarence, KG ( 1387 – 22 March 1421 ), also known as Thomas Plantagenet, was the second son of King Henry IV of England and his first wife, Mary de Bohun.