Married Relationships
Married Relationships is in General Things.
Culture, General Things, Married Relationships, Brother and Sister
Before Jan 279BC Ptolemy Ceraunus King of Macedon 319BC 279BC (age 40) and Arsinoe II 316BC 265BC (age 37) were married. She the daughter of Ptolemy I Soter 367BC 282BC and Berenice I of Egypt 340BC 275BC. He the son of Ptolemy I Soter 367BC 282BC and Eurydice of Egypt. They were brother and sister.
After 273BC Ptolemy II Philadelphus Pharoah of Egypt 309BC 246BC (age 36) and Arsinoe II 316BC 265BC (age 43) were married. No issue. She the daughter of Ptolemy I Soter 367BC 282BC and Berenice I of Egypt 340BC 275BC. He the son of Ptolemy I Soter 367BC 282BC and Berenice I of Egypt 340BC 275BC. They were brother and sister.
In 145BC Ptolemy VIII Physcon 184BC 116BC (age 39) and Cleopatra II 186BC 115BC (age 41) were married. They were brother and sister.
Around 119BC Ptolemy IX Soter 142BC 81BC (age 23) and Cleopatra IV 138BC 112BC (age 19) were married. They were brother and sister.
In 115BC Ptolemy IX Soter 142BC 81BC (age 27) and Cleopatra IV 138BC 112BC (age 23) were divorced.
In 115BC Ptolemy IX Soter 142BC 81BC (age 27) and Cleopatra Selene of Syria 135BC 130BC (age 20) were married. They were brother and sister.
Around Oct 50BC Ptolemy XIII Theos Philopator 61BC 47BC (age 11) and Cleopatra VII Philopator 69BC 30BC (age 19) were married. They were brother and sister.
After 13 Jan 47BC Ptolemy XIV Philopator 59BC 44BC and Cleopatra VII Philopator 69BC 30BC (age 22) were married. They were brother and sister.
Culture, General Things, Married Relationships, First Cousin Heading
Culture, General Things, Married Relationships, Second Cousin
Culture, General Things, Married Relationships, Third Cousin and Above
Culture, General Things, Married Relationships, Uncles and Aunts
Aunt and Nephew
Around 1354 Baldwin Montfort and Margaret Clinton (age 4) were married. They were aunt and nephew. She a great x 5 granddaughter of King Henry "Curtmantle" II of England. 
In 1496 Ferdinand II King Naples (age 26) and Joanna Trastámara Queen Consort Naples (age 16) were married. She the daughter of Ferdinand I King Naples and Joanna of Aragon Queen Consort Naples (age 42). He the son of Alfonso II King Naples and Ippolita Maria Sforza. They were aunt and nephew.
Great Uncle and Niece
After 1464 James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale and Beatrix Sinclair Countess Douglas and Avondale were married. She by marriage Countess Douglas, Countess Avondale. The difference in their ages was 27 years. She the daughter of Henry Sinclair 2nd Earl Orkney and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney. He the son of Archibald "Grim" Douglas 3rd Earl Douglas and Joanna Strathearn Countess Douglas. They were great uncle and niece.
In or before 1498 Maurice Fitzgerald 9th Earl Desmond and Ellen Roche Countess Desmond (age 32) were married. He the son of Thomas Fitzgerald 7th Earl Desmond and Ellice Barry Countess Desmond. They were great uncle and niece. He a great x 5 grandson of King Edward "Longshanks" I of England. 
On 19 Oct 1505 Ferdinand II King Aragon (age 53) and Germaine Foix Queen Consort Aragon (age 17) were married. She by marriage Queen Consort Aragon. The difference in their ages was 35 years. She the daughter of Jean Foix Count Étampes and Marie Valois Viscountess Narbonne. He the son of John II King Aragon and Juana Enríquez Queen Consort Aragon. They were great uncle and niece.
On 17 Jul 1701 Sewster Peyton 2nd Baronet and Anne Dashwood Lady Peyton were married. She by marriage Lady Peyton of Doddington. They were great uncle and niece.
Around 1850 Sassoon David Sassoon (age 17) and Flora Gubbay aka Sassoon were married. The difference in their ages was 27 years. They were great uncle and niece.