Jean I Grimaldi (Giovanni I Grimaldi) (c. 1382 â 1454) was Lord of Monaco three times; 1395, jointly with his brothers Ambroise and Anthony II from 1419 to 1436, and he held the title by himself from 1436 until 1454. He died on 8 May 1454, aged 71 or 72, and was succeeded by his son Catalan I Grimaldi.