All Saint’s Day is a Holy Day of Obligation

From 9:00am

On May 13, 609 A.D. Pope Boniface IV dedicated the Pantheon in Rome in honor of all Christian martyrs, and the Catholic feast of All Martyrs Day was established in the Western church. Pope Gregory III later expanded the feast day to include all saints as well as all martyrs and moved the observance from May 13th to November 1st.