Me write this in your own words it's about all saints day 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 festival to include all saints as well as all martyrs, and moved the observance from may 13 to november 1. by the 9th century the influence of christianity had spread into celtic lands, where it gradually blended with and supplanted the older celtic rites. in 1000 a. d., the church would make november 2 all souls’ day, a day to honor the dead. it’s widely believed today that the church was attempting to replace the celtic festival of the dead with a related church-sanctioned holiday.

The celebration of All Saints Day dates back to the 7th century A.D., when the Roman temple known as the Pantheon was dedicated by Pope Boniface IV to all Christian martyrs. This took place on May 13, 609 A.D., and this date became a festival, and its scope was extended to include all saints. The date of the festival was later moved to November 1, by Pope Gregory III.

The Roman temple had been turned into a Catholic church. A similar syncretism occurred in the 9th century. Christianity had reached Celtic lands, and little by little Celtic festivals and rites were replaced by Christian ones. November 2 was a date when the Celts honored their dead. Given its closeness to November 1, it was assimilated to Christian festivities and has been known as All Souls Day since the year 1000 A.D.