Constance of Béarn
Constance (died 1310) was "suo jure" Viscountess of Marsan as well as titular Countess of Bigorre, daughter of Gaston VII, Viscount of Béarn and his first wife Martha of Marsan.
Constance inherited all of her titles from her mother and contended to inherit her father's Viscounty of Béarn.
She was married three times during her lifetime, marrying into the royal families of Aragon, Castile and England. "
Frederick II, Count of Vaudémont
Frederick( Ferry) II of Lorraine- Vaudémont( – 31 August 1470), was Count of Vaudémont and Lord of Joinville from 1458 to 1470.
He was son of Antoine of Lorraine, Count of Vaudémont and Lord of Joinville and Marie of Harcourt, Countess of Harcourt and Aumale, as well as Baroness of Elbeuf.
He is sometimes numbered Frederick V by continuity with the Dukes of Lorraine.
In 1445, he married his cousin Yolande of Anjou( 1428 – 1483), daughter of René I of Anjou,( King of Naples, Duke of Anjou, of Bar and of Lorraine, Count of Provence), and of Isabelle, Duchess of Lorraine.
This marriage put an end to the litigation which existed between the fathers of the bride and groom, in connection with the succession of the Duchy of Lorraine.
They had six children:
In 1453 his father- in- law honoured him with the command of the troops that he sent to the Dauphin Louis to help him to fight the Duke of Savoy.
In 1456 René entrusted the government of the Duchy of Bar to Frederick, and in 1459 granted him the honorary title of Lieutenant- General of Sicily.
Marie Louise de Rohan
Marie Louise de Rohan (Marie Louise Geneviève; 7 January 1720 – 4 March 1803), also known as Madame de Marsan, was the governess of Louis XVI of France and his siblings.
She was an influential figure of the French court and a driving force of the Dévots and the conservative fraction of the court nobility.
Jean, Count of Harcourt
John of Lorraine- Vaudémont( died 1473) was a younger son of Antoine of Lorraine, Count of Vaudémont and Marie of Harcourt.
He was Count of Harcourt and Count of Aumale, as well as Baron of Elbeuf.
His mother was the eldest daughter of John VII of Harcourt, Count of Harcourt and Aumale.
Her brother, John VIII of Harcourt, her father's heir, died in 1424.
In anticipation of this, she assigned to John the County of Harcourt in 1448.
In 1449, at the breakdown of the Truce of Tours, he was sent as an ambassador to Philip III, Duke of Burgundy, by King Charles VII of France.
In 1452, his maternal grandfather died.
John attempted to secure the whole inheritance for himself and his mother.
After his father, he was Count of Harcourt and Count of Aumale( as" John VI").
While briefly effective, by 1454, his mother's younger sister had gained control of the County of Aumale.
He was appointed captain of Angers in 1469, and later seneschal and governor of Anjou.
He died in 1473, unmarried, and was succeeded by his nephew, René II, Duke of Lorraine.
Martha, Viscountess of Marsan
Martha of Marsan( also known as" Mathe" or" Amata") was a daughter of Petronilla, Countess of Bigorre by her fifth husband Boson of Marsan.
Her dates of birth and death are disputed, though it is believed that she was born soon after the marriage of her parents in 1228 and died after she claimed Bigorre in 1283.
She was" suo jure" Viscountess of Marsan, which she inherited from her father.
Claude Françoise de Lorraine
Claude of Lorraine (6 October 1612 – 2 August 1648) was a daughter of Henry II, Duke of Lorraine, and Margerita Gonzaga, her sister was Nicole, Duchess of Lorraine.
She married her first cousin and was the Duchess of Lorraine by marriage.
Gaston, Count of Marsan
Gaston de Lorraine (Gaston Jean Baptiste Charles; 7 February 1721 – 2 May 1743) was a French nobleman and member of a cadet branch of the House of Lorraine.
He was the last Count of Marsan.
His wife was Marie Louise de Rohan.
Charles, Count of Marsan
Charles de Lorraine( 8 April 1648 – 13 November 1708) was the Count of Marsan.
He was the youngest son of the Count of Harcourt and brother of the Chevalier de Lorraine.
Camille, Prince of Marsan
Camille de Lorraine( Louis Camille; 18 December 1725 – 12 April 1780) was a French nobleman and Prince of Lorraine.
He was known as the" Prince of Marsan" and after the death of his father, was the Count of Marsan.
Charles Henri, Prince of Commercy
Charles Henri of Lorraine( 17 April 1649 – 14 January 1723) was the legitimated son of Charles IV, Duke of Lorraine, and Béatrix de Cusance.
He was given the Principality of Commercy in 1708 by his cousin Leopold, Duke of Lorraine.
He was also the Count of Falkenstein.

Question: When did Gaston, Count Of Marsan's wife die?
Answer: 4 March 1803