Roman Empire acceded to the Concordat of Worms, accepting the papal decision. From about 1600, certain Catholic monarchs claimed a jus exclusivae (right of exclusion), i.e. a veto over papal elections, exercised through a crown-cardinal. By an informal convention, each state claiming the veto could exercise the right once per conclave. Therefore, a crown-cardinal did not announce his veto until the very last moment when the candidate in question seemed likely to get elected. No vetoes could be employed after an election. After the Holy Roman Empire dissolved in 1806, its veto power devolved upon the Austrian Empire. The last exercise of the veto occurred in 1903, when Prince Jan Puzyna de Kosielsko informed the College of Cardinals that Austria opposed the election of Mariano Rampolla. Consequently, the college elected Giuseppe Sarto as Pope Pius X, who issued the constitution Commissum nobis six months later, declaring that any cardinal who communicated his government's veto in the future would suffer excommunication latae sententiae. Seclusion and resolution To resolve prolonged deadlocks in papal elections in the earlier years, local authorities often resorted to the forced seclusion of the cardinal electors, such as first in the city of Rome in 1241, and possibly before that in Perugia in 1216. In 1269, when the forced seclusion of the cardinals alone failed to produce a pope, the city of Viterbo refused to send in any materials except bread and water. When even this failed to produce a result, the townspeople removed the roof of the Palazzo dei Papi in their attempt to speed up the election. In an attempt to avoid future lengthy elections, Gregory X introduced stringent rules with the 1274 promulgation of Ubi periculum. Cardinals were to be secluded in a closed area and not accorded individual rooms. No cardinal was allowed, unless ill, to be attended by more than two servants. Food was supplied through a window to avoid outside contact. After three days of the conclave, the cardinals were to receive only one dish a day; after another five days, they were to receive just bread and water. During the conclave, no cardinal was to receive any ecclesiastical revenue. Adrian V abolished Gregory X's strict regulations in 1276, but Celestine V, elected in 1294 following a two-year vacancy, restored them. In 1562 Pius IV issued a papal bull that introduced regulations relating to the enclosure of the conclave and other procedures.