 He is usually considered the first lord ("signore") of Padua, his election marking the transition from commune "ad singularem dominum" (to a single lord), a characteristic regime known as a "signoria" to contemporaries.Jacopo, a Guelph, led the Paduans to war against Verona in 1311 over the disputed possession of Vicenza.In response to the threat of the Ghibellines and continuous internal feuding, shortly after 25 July 1318 the Paduan aristocracy elected Jacopo as "defensor", "protector", and "gubernator" in perpetuity.