Simon de Montfort (died 1188)
Simon de Montfort (died 1188), sometimes known as Simon IV de Montfort, was lord of Montfort-l'Amaury from 1181 to 1188.
He was the son of Simon III de Montfort, Count of Évreux and Lord of Montfort-l'Amaury.
On his death, Simon III left the comté of Évreux to his elder son Amaury V, and his French properties in Montfort-l'Amaury and Rochefort-en-Yvelines to Simon.
Montfort married Amicia, daughter of Robert de Beaumont, 3rd Earl of Leicester.
They had two sons and a daughter:
Eleanor de Montfort, Princess of Wales
Eleanor de Montfort, Princess of Wales and Lady of Snowdon( 1252 – 19 June 1282) was an English noble.
She was the daughter of Simon de Montfort, 6th Earl of Leicester and Eleanor of England.
She was also the second woman who can be shown to have used the title Princess of Wales.
Amaury de Montfort (died 1241)
Amaury de Montfort( 1192 – 1241) was the son of Simon de Montfort, 5th Earl of Leicester and Alix de Montmorency, and the brother of Simon de Montfort, 6th Earl of Leicester.
Simon III de Montfort
Simon III de Montfort (1117 – 13 March 1181), called the Bold, was count of Évreux from 1140 until 1181 and the seigneur de Montfort-l'Amaury from 1137 to 1181.
He was the son of Amaury III the seigneur de Montfort-l'Amaury and count of Evreux and Agnès de Garlande, daughter of Anseau de Garlande.
Guy de Montfort, Count of Nola
Guy de Montfort, Count of Nola( 1244 – 1291) was the son of Simon de Montfort, 6th Earl of Leicester and Eleanor of England.
William Marmion, Baron Marmion of Torrington
William Marmion, Baron Marmion of Torrington, was an English clergyman and member of Simon de Montfort's Parliament.
Simon de Montfort, 5th Earl of Leicester
Simon de Montfort, 5th Earl of Leicester( – 25 June 1218), known as Simon IV( or V) de Montfort and as Simon de Montfort the Elder, was a French nobleman and soldier who took part in the Fourth Crusade( 1202 – 1204) and was a prominent leader of the Albigensian Crusade.
He died at the Siege of Toulouse in 1218.
He was lord of Montfort- l' Amaury in France and Earl of Leicester in England.
Amaury de Montfort (priest)
Amaury de Montfort( 1242 or 1243 – 1301) was the third son of parliamentary pioneer Simon de Montfort, 6th Earl of Leicester, and Eleanor of England, daughter of King John.
Amaury entered the priesthood as a young man, and held the positions of Treasurer of York Cathedral, canon of Rouen, Évreux, London and Lincoln.
He served as a papal chaplain as well.
After the deaths of his father and older brother Henry de Montfort at the Battle of Evesham in 1265( by men under the command of then Prince Edward, later Edward I, aka Edward Longshanks), Amaury fled to France with his mother, younger sister, and surviving brothers.
Amaury de Montfort soon began studying medicine and theology at the University of Padua.
His older brothers, Guy de Montfort, Count of Nola and Simon de Montfort the Younger were seeking their fortunes in Italy.
A tragic turn of events lead to the bloody 1271 confrontation between Guy and Simon and their cousin Henry of Almain( also Edward's cousin, by virtue of his father, Henry III being the elder brother of both Eleanor of England and Henry of Almain's father, Richard, Earl of Cornwall).
Henry, whom the de Montfort sons considered a traitor to their father's ideals, was attacked during mass at Viterbo, and murdered on the altar steps, resulting in the excommunication of both de Montfort sons.
While Amaury was not in Viterbo, and was not involved in the murder, Edward swore vengeance upon all of Simon de Montfort's sons, Amaury included.
Simon the younger died that year, reportedly of a tertian fever, while Guy managed to appeal to the pope( with the aid of his father- in- law), resulting in his return to the church.
In 1275, after the death of his mother at Montargis Abbey, Amaury, by then a Papal Chaplain, accompanied his younger sister Eleanor de Montfort on a winter sea voyage to Wales and her new husband, Llywelyn ap Gruffudd( the grandson of Llywelyn Fawr).
Intercepted at sea by mercenaries in the employ of now King Edward I, both Amaury and Eleanor were taken captive.
Following two paragraphs taken mainly from" Chronica, ascribed to William Rishanger, a monk of St. Albans", ed. Henry Thomas Riley[ 1865], 87, 99.
While Eleanor's captivity was gentle and relatively short- lived( she was married to Prince Llywelyn at King Edward's expense in 1278), Amaury was held' without rigour' in Corfe Castle and later in Sherborne Castle.
After requests from the Pope, Prince Llywelyn and Archbishop John Peckham of Canterbury, Amaury was released after swearing at London not to return to England unless invited by the king.
Upon his release in mid April 1282, Amaury returned to France, never again to see his sister, who died in childbirth that very year, mere months before the death of her husband Llewylyn and the annexation of North Wales to the English crown.
Amaury after some years renounced his clerical career and became a knight, apparently dying soon afterwards in Italy, possibly after 1301
Guy de Montfort, Lord of Sidon
Guy de Montfort( died 31 January 1228) was the younger son of Simon de Montfort and Amicia, sister of Robert FitzPernel, Earl of Leicester.
Peter de Montfort
Peter de Montfort( or Piers de Montfort)( c. 1205 – 4 August 1265) of Beaudesert Castle was an English magnate, soldier and diplomat.
He is the first person recorded as having presided over Parliament as a" parlour" or" prolocutor", an office now known as Speaker of the House of Commons.
He was one of those elected by the barons to represent them during the constitutional crisis with Henry III in 1258.
He was later a leading supporter of Simon de Montfort, 6th Earl of Leicester, against the King.
Both he and Simon de Montfort were slain at the Battle of Evesham on 4 August 1265.

Question: What is the date of death of Simon De Montfort (Died 1188)'s father?
Answer: 13 March 1181