Từ Dụ
Từ Dụ or Từ Dũ (20 June 1810 – 12 May 1902), born Phạm Thị Hằng (范氏姮), was the wife of Thiệu Trị and mother of Tự Đức.
Hằng was a daughter of Phạm Đăng Hưng.
She was granted the title Empress Dowager Từ Dụ  after Tự Đức ascended the throne.
Tự Đức died in 1883.
Three regents, Nguyễn Văn Tường, Tôn Thất Thuyết and Trần Tiễn Thành, declared Dục Đức, the eldest adoptive-son of Tự Đức, as the new emperor.
Three days later, they deposed Dục Đức and enthroned Hiệp Hòa.
Từ Dụ was elevated to the position of one of the "Tam Cung" (三宮) together with Trang Ý and Học phi.
Từ Dụ played a significant role in the dethronement of Hiệp Hòa, whom was a pro-French emperor, and enthroned Kiến Phúc.
In 1885, she was granted the title Grand Empress Dowager Từ Dụ .
Tôn Thất Thuyết decided to launch the Cần Vương movement against French colonists.
"
Tam Cung" fled to Tomb of Tự Đức together with Emperor Hàm Nghi.
Thuyết decided to take them to a mountain base at Tân Sở, and then went to China to hide and seek reinforcements. "
Tam Cung" refused, and came back to Huế.
She was granted the title Great Grand Empress Dowager Từ Dụ  by Thành Thái in 1889.
She died in 1902, and was given the posthumous name "Empress Nghi Thiên".
A hospital in Ho Chi Minh City was named after her.
Thành Thái
Thành Thái( 14 March 1869 – 20 March 1954) born Nguyễn Phúc Bửu Lân( 阮福寶嶙), was the son of Emperor Dục Đức and Empress Dowager Từ Minh.
He reigned for 18 years, from 1889 to 1907.
Empress Dowager Duan
Empress Dowager Duan is the name of:
Empress Dowager Dong
Empress Dowager Dong (died 189), personal name unknown, formally known as Empress Xiaoren, was an empress dowager of the Eastern Han dynasty of China.
She was never empress throughout her life because she was the wife of a marquis; she only became empress dowager because her son, Liu Hong (Emperor Ling), became the emperor by chance.
During her son's reign, she developed a rivalry with her daughter-in-law, Empress He, because she wanted Emperor Ling's younger son, Liu Xie, to be crown prince while Empress He wanted her own son, Liu Bian to succeed his father.
Emperor Ling died in 189 before he managed to designate either of his two sons as crown prince.
Liu Bian eventually took the throne as Emperor Shao; Empress Dowager Dong, as the emperor's grandmother, became grand empress dowager, while her daughter-in-law became empress dowager.
Empress Dowager
He eventually conspired with her brother, General-in-Chief He Jin, to unseat her mother-in-law from power.
Grand Empress Dowager Dong died of illness shortly after her downfall; the common people held Empress Dowager He and her family responsible for the grand empress dowager's death.
Thiệu Trị
Thiệu Trị (lit. "inheritance of prosperity"; 6 June 1807 – 4 November 1847), personal name Nguyễn Phúc Miên Tông or Nguyễn Phúc Tuyền, was the third emperor of the Nguyễn Dynasty.
He was the eldest son of Emperor Minh Mạng, and reigned from 14 February 1841 until his death on 4 November 1847.
Lu Huinan
Lu Huinan( 412 – February 24, 466), formally Empress Dowager Zhao( 昭太后, literally" accomplished empress dowager"), semi-formally Empress Dowager Chongxian( 崇憲太后), was an empress dowager of the Chinese dynasty Liu Song.
She had been a concubine of Emperor Wen, and she became empress dowager because her son Liu Jun later became emperor( as Emperor Xiaowu).
Lu Huinan
Lu Huinan( 412 – February 24, 466), formally Empress Dowager Zhao( 昭太后, literally" accomplished empress dowager"), semi-formally Empress Dowager Chongxian( 崇憲太后), was an empress dowager of the Chinese dynasty Liu Song.
She had been a concubine of Emperor Wen, and she became empress dowager because her son Liu Jun later became emperor( as Emperor Xiaowu).
Grand Empress Dowager Shangguan
Grand Empress Dowager Shangguan( 上官太皇太后)( personal name unknown)( 89 BC – 37 BC), also known as Empress Shangguan( 上官皇后), Empress Xiaozhao( 孝昭皇后) and Empress Dowager Shangguan( 上官太后), was an Empress, Empress Dowager and Grand Empress Dowager during the Han Dynasty and wife of Emperor Zhao.
Her father was Shangguan An( 上官安), the son of Shangguan Jie( 上官桀).
Her mother was the daughter of Huo Guang.
She was a key figure in a number of political incidents during the middle Han Dynasty, and she spent her entire adult life as a Grand Empress Dowager and a widow without family.
Both sides of her family were wiped out in two separate mass executions as punishment for being relatives of individuals accused of seeking to usurp the throne.
She remains the youngest person in Chinese history to assume the titles of both Empress Dowager and Grand Empress Dowager.
Empress Dowager Bo
Empress Dowager Bo( 薄太后) was an imperial concubine of Emperor Gaozu of Han( Liu Bang).
She was also known as Consort Bo( 薄姬) during the life of the Emperor, and more formally as either Empress Dowager Xiaowen( 孝文太后) or( rarer) Empress Gao( 高皇后).
Despite being a concubine of lower standing, her son, Liu Heng, became Emperor Wen of Han, cementing her place in history.
The year of her birth is not known.
She died in 155 BC.
Empress Dowager
Bo is formally the first grand empress dowager in Chinese history, as Empress Dowager Lü, the only other empress dowager till then who lived to see her grandson become emperor, never claimed the title.
Empress Dowager Dong
Empress Dowager Dong (died 189), personal name unknown, formally known as Empress Xiaoren, was an empress dowager of the Eastern Han dynasty of China.
She was never empress throughout her life because she was the wife of a marquis; she only became empress dowager because her son, Liu Hong (Emperor Ling), became the emperor by chance.
During her son's reign, she developed a rivalry with her daughter-in-law, Empress He, because she wanted Emperor Ling's younger son, Liu Xie, to be crown prince while Empress He wanted her own son, Liu Bian to succeed his father.
Emperor Ling died in 189 before he managed to designate either of his two sons as crown prince.
Liu Bian eventually took the throne as Emperor Shao; Empress Dowager Dong, as the emperor's grandmother, became grand empress dowager, while her daughter-in-law became empress dowager.
Empress Dowager
He eventually conspired with her brother, General-in-Chief He Jin, to unseat her mother-in-law from power.
Grand Empress Dowager Dong died of illness shortly after her downfall; the common people held Empress Dowager He and her family responsible for the grand empress dowager's death.

Question: When did Từ Dụ's husband die?
Answer: 4 November 1847