Why was Pope Pius IX anrgy when the new king was installed?

Pope Pius IX was angered by the installation of the new king, Victor Emmanuel II of Italy, because it symbolized the unification of Italy, which resulted in the annexation of the Papal States and a significant reduction of the Church's temporal power. The Pope viewed this as a direct challenge to papal authority and sovereignty, leading to his declaration of the "Prisoner of the Vatican" as he refused to recognize the legitimacy of the new Italian state. This deeply strained the relationship between the Catholic Church and the Italian government, fostering long-lasting tensions.