See also
| Husband: | Lambert I + (765-836) | |
| Wife: | Adelaide of LOMBARDY (c. 775- ) | |
| Children: | Guy (c. 795- ) | |
| Name: | Lambert I + | |
| Sex: | Male | |
| Father: | Gui + (745-814) | |
| Mother: | - | |
| Birth | 0765 | Nantes, Loire-Atlantique, Anjou, France |
| Title | frm 0818 to 0831 (age 52-66) | Count of Nantes |
| Occupation | Count of Nantes | |
| Title | frm 0834 to 0836 (age 68-71) | Duke of Spoleto |
| Death | 1 Sep 0836 (age 70-71) | |
| Name: | Adelaide of LOMBARDY | |
| Sex: | Female | |
| Father: | - | |
| Mother: | - | |
| Birth | 0775 (est) | |
| Name: | Guy | |
| Sex: | Male | |
| Birth | 0795 (est) | |
Lambert I was the Count of Nantes and Prefect of the Breton March between 818 to 831 and Duke of Spoleto between 834 and 836. Lambert succeeded his father Guy.
Lambert participated in an expedition undertaken by Louis the Pious in 818 against the Bretons, who had proclaimed Morvan Lez-Breizh their king. In 822, a new Breton chief Wiomarc'h rebelled, but submitted in May 825 at Aachen. On his return to Brittany, Lambert had him assassinated.
In 831, Lambert joined the rebellion of Lothair I against Louis and was exiled across the Alps, where he was given the Duchy of Spoleto in 834. He was one of many among Lothair's entourage to die in an epidemic of 836.
Lambert married firstly Itta, who bore his eventual successor in Nantes, Lambert II. Subsequently, he married Adelaide of Lombardy, the eldest daughter of Pepin of Italy, who was in turn the eldest son of Charlemagne that had children. Adelaide bore him another son, Guy, who would succeed him in the duchy of Spoleto. Guy's son Guy III of Spoleto was a descendant of Charlemagne through Lambert's wife, Adelaide, and was crowned Holy Roman Emperor.