Question: What is the date of death of Euphrosyne (9Th Century)'s mother?

Knowledge 1: Euphrosyne (9th century)
Euphrosyne (Greek: Εὐφροσύνη; 790 – after 836), was a Byzantine empress by marriage to Michael II.She was a daughter of Byzantine emperor Constantine VI, the last representative of the Isaurian dynasty, and his empress Maria of Amnia. [SEP] Knowledge 2: Maria of Amnia
Maria of Amnia (770 – after 823) was a Byzantine empress, the first wife of Constantine VI.She was a granddaughter of Saint Philaretos, a magnate from the Armeniakon Theme known for his charitable activities, a relation mentioned in his hagiography.The name of her father is unknown and her mother has been identified as Hypatia by Christian Settipani.Maria was born in Amnia, Paphlagonia.
Knowledge 1: Euphrosyne (9th century)
Euphrosyne (Greek: Εὐφροσύνη; 790 – after 836), was a Byzantine empress by marriage to Michael II.She was a daughter of Byzantine emperor Constantine VI, the last representative of the Isaurian dynasty, and his empress Maria of Amnia. [SEP] Knowledge 2: Euphrosyne of Masovia
Euphrosyne of Masovia also known as" Eufrozja"( 1292–1328/1329) was Duchess of Oświęcim by her marriage.Euphrosyne was the daughter of Boleslaus II of Masovia, Prince of Plock and his second wife Kunigunde, daughter of Ottokar II of Bohemia.The genesis of her name is unknown.This is the first and the last time that princess of Masovian lineage of Piast was named Eufrozyna.Modern Polish historians usually named her" Eufrozyna", but in sources she was mentioned mostly as" Eufrazja".Her younger brother was Prince Wenceslaus of Płock( ca. 1295- 1336).According to older historians Euphrosyne had also sister Berta, but she was midget from Euphrosyne's mother court.Eufrozyna had also siblings from previous father's marriage.They were Siemowit II, Trojden I and wife of Władysław Prince of Leginca( her name is unknown).The date of birth of Euphrosyne is unknown.Her parents married in 1291, so she could be born not earlier than in 1292.According to genealogist Oswald Balzer Euphrosyne was born in 1292.This theory was based on fact that she must be at least 14 years old, when she get married in 1306( her son Jan I was born in 1307).The exact date of Euphrosyne's marriage to Władysław of Oświęcim is unknown.Genealogists assume that the marriage was concluded between 1304 – 1309, indicating the year 1306.The couple were already connected by a marriage.Euphrosyne's cousin Wenceslaus III of Bohemia was married to Władysław's sister Viola Elisabeth of Cieszyn.This marriage would bring more connections between the Euphrosyne's husband died between 15 December 1321 and 15 May 1324.She participated in the regency of her son John, who was now ruler of the duchy of Oświęcim.She participated in the government until at least 14 November 1328.It was the last time that she was mentioned in documents.According to" Nekrolog dominikanów krakowskich" she died on 26 December.The year of her death is disputed.She may died shortly after 1327, may be yet in 1328.Euphrosyne was buried in the Dominican monastery in Krakow.Euphrosyne and Władysław had two or three children:
Knowledge 1: Maria of Amnia
Maria of Amnia (770 – after 823) was a Byzantine empress, the first wife of Constantine VI.She was a granddaughter of Saint Philaretos, a magnate from the Armeniakon Theme known for his charitable activities, a relation mentioned in his hagiography.The name of her father is unknown and her mother has been identified as Hypatia by Christian Settipani.Maria was born in Amnia, Paphlagonia. [SEP] Knowledge 2: Euphrosyne of Masovia
Euphrosyne of Masovia also known as" Eufrozja"( 1292–1328/1329) was Duchess of Oświęcim by her marriage.Euphrosyne was the daughter of Boleslaus II of Masovia, Prince of Plock and his second wife Kunigunde, daughter of Ottokar II of Bohemia.The genesis of her name is unknown.This is the first and the last time that princess of Masovian lineage of Piast was named Eufrozyna.Modern Polish historians usually named her" Eufrozyna", but in sources she was mentioned mostly as" Eufrazja".Her younger brother was Prince Wenceslaus of Płock( ca. 1295- 1336).According to older historians Euphrosyne had also sister Berta, but she was midget from Euphrosyne's mother court.Eufrozyna had also siblings from previous father's marriage.They were Siemowit II, Trojden I and wife of Władysław Prince of Leginca( her name is unknown).The date of birth of Euphrosyne is unknown.Her parents married in 1291, so she could be born not earlier than in 1292.According to genealogist Oswald Balzer Euphrosyne was born in 1292.This theory was based on fact that she must be at least 14 years old, when she get married in 1306( her son Jan I was born in 1307).The exact date of Euphrosyne's marriage to Władysław of Oświęcim is unknown.Genealogists assume that the marriage was concluded between 1304 – 1309, indicating the year 1306.The couple were already connected by a marriage.Euphrosyne's cousin Wenceslaus III of Bohemia was married to Władysław's sister Viola Elisabeth of Cieszyn.This marriage would bring more connections between the Euphrosyne's husband died between 15 December 1321 and 15 May 1324.She participated in the regency of her son John, who was now ruler of the duchy of Oświęcim.She participated in the government until at least 14 November 1328.It was the last time that she was mentioned in documents.According to" Nekrolog dominikanów krakowskich" she died on 26 December.The year of her death is disputed.She may died shortly after 1327, may be yet in 1328.Euphrosyne was buried in the Dominican monastery in Krakow.Euphrosyne and Władysław had two or three children:

Answer: 823