Serrata del Maggior Consiglio
The Great Council Lockout (Italian: Serrata del Maggior Consiglio) was a constitutional process, started with a 1297 ordinance, by means of which membership of the Great Council of Venice became hereditary. Since it was the Great Council that had the right to elect the Doge, the 1297 ordinance marked a significant change in the constitution of the Republic.
Source: Wikipedia — Serrata del Maggior Consiglio (CC BY-SA 4.0)