In 1329 [his father] John Montfort IV Duke Brittany (age 34) and [his mother] Joanna Dampierre Duchess Brittany (age 34) were married at Chartres [Map]. She the daughter of [his grandfather] Louis Dampierre I Count Nevers and [his grandmother] Joan Rethel Countess Nevers and Rethel. They were fourth cousins. He a great grandson of King Henry III of England.

In 1339 John Montfort V Duke Brittany was born to John Montfort IV Duke Brittany (age 44) and Joanna Dampierre Duchess Brittany (age 44). He a great x 2 grandson of King Henry III of England.

On 16 Sep 1345 [his father] John Montfort IV Duke Brittany (age 50) died at Hennebont. His son John Montfort V Duke Brittany (age 6) succeeded V Duke Brittany 1221 Dreux. [his future wife] Mary Plantagenet Duchess Brittany by marriage Duchess Brittany 1221 Dreux.

Around 03 Jul 1361 John Montfort V Duke Brittany (age 22) and Mary Plantagenet Duchess Brittany (age 16) were married. She the daughter of King Edward III of England (age 48) and Philippa of Hainault Queen Consort England (age 47). They were third cousins. He a great x 2 grandson of King Henry III of England.

In Sep 1361 [his wife] Mary Plantagenet Duchess Brittany (age 16) died.

In May 1366 John Montfort V Duke Brittany (age 27) and Joan Holland Duchess Brittany (age 16) were married. She by marriage Duchess Brittany 1221 Dreux. She the daughter of Thomas Holland 1st Earl Kent and Joan "Fair Maid of Kent" Princess Wales (age 37). They were third cousins. He a great x 2 grandson of King Henry III of England. She a great granddaughter of King Edward I of England.

Before 13 Oct 1370 [his brother-in-law] Thomas Holland 2nd Earl Kent (age 20) and Alice Fitzalan Countess Kent (age 20) were married. She by marriage Countess Kent. She the daughter of Richard Fitzalan 10th Earl of Arundel 8th Earl of Surrey (age 64) and Eleanor Plantagenet Countess Arundel and Surrey (age 52). He the son of Thomas Holland 1st Earl Kent and [his mother-in-law] Joan "Fair Maid of Kent" Princess Wales (age 42). They were third cousins. He a great grandson of King Edward I of England. She a great x 2 granddaughter of King Henry III of England.

In 1372 John Montfort V Duke Brittany (age 33) succeeded 6th Earl Richmond. [his wife] Joan Holland Duchess Brittany (age 22) by marriage Countess Richmond.

In Sep 1374 [his mother] Joanna Dampierre Duchess Brittany (age 79) died.

After 24 Jun 1380 John Hastings 3rd Earl Pembroke (age 7) and Elizabeth Lancaster Duchess Exeter (age 17) marriage annulled since she had become pregnant by [his brother-in-law] John Holland 1st Duke Exeter (age 28) whom she subsequently married. It isn't clear whether John Holland was punished; he was half-brother to [his brother-in-law] King Richard II of England (age 13) through their mother [his mother-in-law] Joan "Fair Maid of Kent" Princess Wales (age 51).

In 1384 [his wife] Joan Holland Duchess Brittany (age 34) died.

On 02 Oct 1386 John Montfort V Duke Brittany (age 47) and Joanna of Navarre Queen Consort England (age 16) were married at Saillé [Map]. She by marriage Duchess Brittany 1221 Dreux, Countess Richmond. His third marriage, her first. The marriage proceeded when her father Charles "Bad" II King Navarre (age 53) agreed to give his daughter 120,000 gold francs and to pay 6,000 francs owed to John, duke of Brittany, for the rent of certain lands. He, John, gave her the cities of Nantes [Map] and Guerrand [Map]. The difference in their ages was 31 years. She the daughter of Charles "Bad" II King Navarre and Joan Valois Queen Consort Navarre. They were second cousin twice removed. He a great x 2 grandson of King Henry III of England. She a great x 4 granddaughter of King Henry III of England.

On 12 Aug 1387 [his son] Jeanne Montfort was born to John Montfort V Duke Brittany (age 48) and [his wife] Joanna of Navarre Queen Consort England (age 17). He a great x 3 grandson of King Henry III of England.

In Oct 1388 [his daughter] Isabelle Montfort was born to John Montfort V Duke Brittany (age 49) and [his wife] Joanna of Navarre Queen Consort England (age 18). She died two months later in Dec 1388. She a great x 3 granddaughter of King Henry III of England.

On 24 Dec 1389 [his son] John Montfort V Duke Brittany was born to John Montfort V Duke Brittany (age 50) and [his wife] Joanna of Navarre Queen Consort England (age 19). He a great x 3 grandson of King Henry III of England.

On 18 Feb 1391 [his daughter] Marie Montfort Duchess Alençon was born to John Montfort V Duke Brittany (age 52) and [his wife] Joanna of Navarre Queen Consort England (age 21). She a great x 3 granddaughter of King Henry III of England.

In 1392 [his daughter] Marguerite Montfort Viscountess Rohan was born to John Montfort V Duke Brittany (age 53) and [his wife] Joanna of Navarre Queen Consort England (age 22). She a great x 3 granddaughter of King Henry III of England.

On 24 Aug 1393 [his son] Arthur Montfort III Duke Brittany was born to John Montfort V Duke Brittany (age 54) and [his wife] Joanna of Navarre Queen Consort England (age 23). He a great x 3 grandson of King Henry III of England.

In 1395 [his son] Richard Montfort was born to John Montfort V Duke Brittany (age 56) and [his wife] Joanna of Navarre Queen Consort England (age 25). He a great x 3 grandson of King Henry III of England.

In Aug 1396 [his son] John Montfort V Duke Brittany (age 6) and [his daughter-in-law] Joan Valois Duchess Brittany (age 5) were married. She by marriage Duchess Brittany 1341 War of Sucession. She the daughter of Charles "Beloved Mad" VI King France (age 27) and Isabeau Wittelsbach Queen Consort France (age 26). He the son of John Montfort V Duke Brittany (age 57) and [his wife] Joanna of Navarre Queen Consort England (age 26). They were second cousins. He a great x 3 grandson of King Henry III of England. She a great x 5 granddaughter of King Henry III of England.

Chronicle of St Denis Book 17 Chapter 9. [Aug 1396]. In the beginning of August, as a sign of the marriage to be consummated between the daughter of the King of France, [his daughter-in-law] Joanna (age 5), still three years old, and [his son] John (age 6), the son of the Duke of Brittany (age 57), a five-year-old youth, a solemn wedding banquet was celebrated in Paris in the presence of the king, the queen, the Duke of Brittany, and the lords of France. Although the betrothal had been agreed upon and confirmed between the parents of both after the year had already passed, since they were related in the third degree of consanguinity¹ on the side of the duke’s wife, Pope Benedict had delayed granting a dispensation on this matter. Moreover, the king did not grant any portion from the kingdom to the daughter, but promised three hundred thousand crowns of gold for the marriage, to be paid at certain terms after both reached marriageable age.

In principio augusti, in signum matrimonii consummendi inter filiam regis Francie Johannam, adhuc triennem, Johannemque filium ducis Britanie, adolescentem quinquennem, Parisius , in regis, regine, ducis Britanie et dominorum Francie presencia , nupciarum solemne celebratum est prandium. Quamvis anno jam transacto inter parentes amborum concordata et confirmata fuissent sponsalia, quia tamen in tercio gradu consanguinitatis ex parte uxoris ducis se mutuo attinebant, super hoc summus pontifex Benedictus distulerat dispensare. Eidem autem filie rex de regno nullam concessit porcionem , sed trecenta milia scuta auri promisit propter nupcias, certis terminis persolvenda, postquam annos nubiles uterque attigisset.

Note 1. John and Joanna were second cousins once removed.

In 1397 [his daughter] Blanche Montfort Countess Armagnac was born to John Montfort V Duke Brittany (age 58) and [his wife] Joanna of Navarre Queen Consort England (age 27). She a great x 3 granddaughter of King Henry III of England.

On 01 Nov 1399 John Montfort V Duke Brittany (age 60) died. His son [his son] John Montfort V Duke Brittany (age 9) succeeded V Duke Brittany 1221 Dreux.

On 10 Jun 1437 [his former wife] Joanna of Navarre Queen Consort England (age 67) died at Havering atte Bower, Essex [Map].