Jews all over the world announce the new month on the Shabbat before it with a text known as “birkat ha-ḥodesh” or blessing the month. In many rites, such as the Western Sephardic and Moroccan rites, the fast days 17 Tammuz and 10 Tevet are also announced on the Shabbat before them with a text known as “hazkarat tsomot” or announcing fasts. But to my knowledge, only the Italian rite (and possibly the ancient Eretz Yisrael rite from which much of it derives) have a custom of announcing Pesaḥ on the Shabbat before it. This passage, the Announcement of Pesaḥ (Azcaràd Pesah in Italian traditional pronunciation) is recited on the Shabbat before Pesaḥ, commonly known as Shabbat haGadol (Sciabbàd Aggadòl), after the reading from the Torah. Citing the mystical hekhalot literature, it celebrates the sages who established the rules of the calendar.