Erard I, Count of Brienne
Erard I, Count of Brienne( 1060 – 1114) was Count of Brienne at the end of the 11th century.
He was the son of Gautier I of Brienne, count of Brienne, and his wife Eustachie of Tonnerre.
In 1097 he fought in the First Crusade.
In 1110 he married Alix of Roucy- Ramerupt, daughter of André de Montdidier- Roucy, seigneur de Ramerupt.
They had 3 children:
Erard II, Count of Brienne
Erard II of Brienne( died 1191) was count of Brienne from 1161 to 1191, and a French general during the Third Crusade, most notably at the Siege of Acre.
He was the son of Gautier II, count of Brienne, and Adèle of Baudemont, daughter of Andrew, lord of Baudemont and Agnes of Braine.
His paternal grandparents were Erard I, Count of Brienne and Alix de Roucy.
During this siege he saw his brother André of Brienne die on 4 October 1189, before being killed himself on 8 February 1191.
Erard II's nephew was Erard of Brienne- Ramerupt.
Before 1166 he married Agnès of Montfaucon( † after 1186), daughter of Amadeus II of Montfaucon and of Béatrice of Grandson- Joinville.
Their children were:
Alphonso of Brienne
Alphonso of Brienne or Alphonse I de Brienne, called Alphonse d'Acre (c. 1228 –
August 25, 1270) was the son of John of Brienne and Berengaria of León, born in Acre.
He was the Grand Butler of France in 1258.
By his marriage (bef. 1250) to Marie, Countess of Eu
he became Count of Eu.
He was also Grand Chamberlain of France, and died in Tunis on the Seventh Crusade.
He had at least two children by Marie:
John I of Brienne, Count of Eu
John I of Brienne( died 12 June 1294) was the son of Alphonso of Brienne and Marie de Lusigan.
His mother was the heiress of Eu, Seine- Maritime, and he succeeded his father as Count of Eu in 1270.
He married Beatrice, the daughter of Guy III, Count of Saint- Pol.
They had: John died at Clermont- en- Beauvaisis in 1294.
Hugh, Count of Brienne
Hugh, Count of Brienne and Lecce( – 9 August 1296) was the second surviving son of Count Walter IV of Brienne and Marie de Lusignan of Cyprus.
Sohier, Count of Enghien
Sohier of Enghien( died March 21, 1364) was the titular Duke of Athens, and Count of Brienne and Lord of Enghien from 1356 to 1364.
The second, but eldest surviving son of Walter of Enghien(" Gautier III d' Enghien") and Isabella of Brienne, when his mother divided the inheritance of his uncle Walter VI of Brienne among her sons, he received the title of Duke of Athens.
He was executed by Albert, Duke of Bavaria in 1364, leaving the titular Duchy to his son
Mary of Lusignan, Countess of Brienne
Mary of Lusignan (French: Marie de Lusignan; before March 1215 – 5 July 1251 or 1253), was the wife of Count Walter IV of Brienne and Countess of Brienne from the time of her marriage in 1233 to her husband's death while on Crusade in 1244.
Mary's parents were King Hugh I of Cyprus and Alice of Champagne, making her a maternal granddaughter of Queen Isabella I of Jerusalem.
Her two surviving sons were John, Count of Brienne, and Hugh of Brienne.
Theodred II (Bishop of Elmham)
Theodred II was a medieval Bishop of Elmham.
The date of Theodred's consecration unknown, but the date of his death was sometime between 995 and 997.
John, Count of Brienne
John, Count of Brienne( c. 1235 – c. 1260) was the eldest son of Walter IV of Brienne and Marie of Lusignan, a princess of Cyprus.
He inherited the County of Brienne on his father's death in 1246, but preferred to live among his mother's relatives at the court of Cyprus, and played little part in international politics.
In 1255, he married Marie, Lady of Thieusies( in Hainaut), the daughter of Sohier II of Enghien.
They had no children, and when he died, he was succeeded by his brother Hugh.
Berengaria of León
Berengaria of León (1204 – 12 April 1237) was the third wife but only empress consort of John of Brienne, Latin Emperor of Constantinople.
According to the chronicle of Alberic of Trois-Fontaines, Berengaria was a daughter of Alfonso IX of León and Berengaria of Castile.
She was a younger sister of Ferdinand III of Castile and Alfonso of Molina.

Question: When did Alphonso Of Brienne's mother die?
Answer: 12 April 1237