Sigebert was born in 630 as the eldest son of
Dagobert I,
King of the Franks, and his concubine Ragnetrude. The king recalled and made peace with
Saint Amand, who was previously banished for criticizing the king's vices, and asked him to baptize his new-born son. The ceremony was performed at
Orléans and
Charibert II, Dagobert's half-brother who was
King of Aquitaine at the time, was the god-father. Dagobert assigned the education of Sigebert to
Pepin of Landen, who was the
mayor of the palace in
Austrasia under his father
Chlotar II, until 629. Pepin took the young Sigebert and moved with him to his domains in Aquitane, where they stayed the next three years. In 633, a revolt of the nobles forced Dagobert to make the three-year old Sigebert
king of Austrasia, similar to how his father Chlotar II had made him king of Austrasia in 623. However, he refused to give the power to Pepin of Landen by making him mayor of the palace for the child-king. Instead he had put Sigebert under the tutelage of
Adalgisel as mayor of the palace and the
Bishop of Cologne Saint Cunibert as regent, while keeping Pepin in
Neustria as hostage. In 634 Dagobert's second son,
Clovis II, was born, and the king forced the nobles to accept him as the next king of Neustria and Burgundy, setting up a new division of the empire. On the death of Dagobert in 639, the two Frankish kingdoms became independent once again under Sigebert III and Clovis II. Both kingdoms were under child-kings – Sigebert was around eleven years old and Clovis was five – and were ruled by the respective regents. It was under Seigbert's reign that the
mayor of the palace began to play the most important role in the political life of Austrasia, and he has been described as the first
roi fainéant—do-nothing king—of the
Merovingian dynasty. Pepin replaced Adalgisel as mayor of the palace of Austrasia in 639 but died the following year, in 640, and was replaced by his son
Grimoald. In 640 the
Duchy of Thuringia rebelled against Austrasia in the only war of Sigebert's reign. Grimoald allowed the young king to stand at the head of the army trying to quell the rebellion, but was defeated by
Duke Radulph. The
Chronicle of Fredegar records that the rout left Sigebert weeping in his saddle. Though ineffective as a king, Sigebert had become a pious adult under the tutelage of Pepin and later Saint Cunibert and lived a life of Christian virtue. He used his wealth to establish numerous monasteries, hospitals, and churches, including the
monastery of Stavelot-Malmedy. Sigebert III died of natural causes on 1 February 656 at age 25. He was buried in the Abbey of
Saint Martin near
Metz which he had founded. In 1063 his body, found incorrupt, was taken out of the tomb and moved to the side of the altar. The abbey was demolished in 1552 and the
relics were moved to the
Nancy Cathedral. Sigebert III is revered as a
saint by the
Catholic Church with his
feast day on 1 February. He is the
patron saint of Nancy. == Marriage and succession ==