Lamberto Grimaldi was Lord of Monaco from 16 March 1458. He was married to his cousin Claudine Grimaldi in 1465 to secure the Grimaldi inheritance of Monaco that by the small state's constitution could only pass to male heirs. Lamberto was of the branch of the Grimaldi family which had settled in Antibes while Claudine was of the more powerful Monaco branch.
Lamberto assumed the reins of power in Monaco at a difficult time in its often vulnerable history. Lamberto fought to preserve Monaco's independence, and is said to have "handled diplomacy and the sword with equal talent". He also established the Grimaldi motto "With God's help."