In or before 1259 Walter Burgh 1st Earl Ulster (age 29) and Aveline Fitzjohn Countess Ulster (age 29) were married. She by marriage Countess Ulster. They were fourth cousins.

In or before 1280 Richard "Red Earl" Burgh 2nd Earl Ulster (age 21) and Margaret Burgh Countess Ulster were married. She by marriage Countess Ulster. He the son of Walter Burgh 1st Earl Ulster. They were third cousins.

On 16 Nov 1327 William Donn Burgh 3rd Earl Ulster (age 15) and Maud Plantagenet Countess Ulster (age 17) were married. She by marriage Countess Ulster. She the daughter of Henry Plantagenet 3rd Earl of Leicester 3rd Earl Lancaster (age 46) and Maud Chaworth. They were second cousin once removed. He a great grandson of King Edward "Longshanks" I of England. She a great granddaughter of King Henry III of England.

In 1352 Lionel Plantagenet 1st Duke of Clarence (age 13) and Elizabeth Burgh Duchess of Clarence (age 19) were married. He by marriage Earl Ulster. She was the sole heir of her father and brought the de Burgh inheritance of the lands of Ulster to the marriage. As a consequence of their earlier betrothal he had been called Earl Ulster since 1347. She the daughter of William Donn Burgh 3rd Earl Ulster and Maud Plantagenet Countess Ulster (age 42). He the son of King Edward III of England (age 39) and Philippa of Hainault Queen Consort England (age 37). They were half second cousin once removed. She a great x 2 granddaughter of King Henry III of England.

On 24 Aug 1369 Edmund Mortimer 3rd Earl March, Earl Ulster (age 17) and Philippa Plantagenet Countess March 5th Countess Ulster (age 14) were married at Reading Abbey [Map]. She by marriage Countess March. He by marriage Earl Ulster. She the daughter of Lionel Plantagenet 1st Duke of Clarence and Elizabeth Burgh Duchess of Clarence. He the son of Roger Mortimer 2nd Earl March and Philippa Montagu Countess March (age 37). They were fourth cousins. She a granddaughter of King Edward III of England.

On 07 Oct 1388 Roger Mortimer 4th Earl March 6th Earl Ulster (age 14) and Eleanor Holland Countess March and Ulster (age 17) were married. She by marriage Countess March, Countess Ulster. She the daughter of Thomas Holland 2nd Earl Kent (age 38) and Alice Fitzalan Countess Kent (age 38). He the son of Edmund Mortimer 3rd Earl March, Earl Ulster and Philippa Plantagenet Countess March 5th Countess Ulster. They were second cousin once removed. He a great grandson of King Edward III of England. She a great x 2 granddaughter of King Edward "Longshanks" I of England.

In 1415 Edmund Mortimer 5th Earl March 7th Earl Ulster (age 23) and Anne Stafford Duchess Exeter were married. She by marriage Countess March, Countess Ulster. She the daughter of Edmund Stafford 5th Earl Stafford and Anne of Gloucester Plantagenet Countess Eu and Stafford (age 32). He the son of Roger Mortimer 4th Earl March 6th Earl Ulster and Eleanor Holland Countess March and Ulster. They were second cousin once removed. He a great x 2 grandson of King Edward III of England. She a great granddaughter of King Edward III of England.

In Oct 1429 Richard Plantagenet 3rd Duke York (age 18) and Cecily "Rose of Raby" Neville Duchess York (age 14) were married. She by marriage Countess Cambridge Countess Ulster. She was the youngest sister of Richard's brother-in-arms Richard Neville Earl Salisbury (age 29). She the daughter of Ralph Neville 1st Earl of Westmoreland and Joan Beaufort Countess of Westmoreland (age 50). He the son of Richard of Conisbrough 1st Earl Cambridge and Anne Mortimer. They were second cousins. He a great grandson of King Edward III of England. She a great granddaughter of King Edward III of England.