Allhallowtide, Hallowtide, Allsaintstide, or the Hallowmas season, is the triduum encompassing the Western Christian observances of All Saints' Eve (Halloween), All Saints' Day (All Hallows') and All Souls' Day, which last from October 31 to November 2 annually. Allhallowtide is a "time to remember the dead, including martyrs, saints, and all faithful departed Christians." The present date of Hallowmas (All Saints' Day) and thus also of its vigil (Hallowe'en) was established for Rome perhaps by Pope Gregory III (731-741) and was made of obligation throughout the Frankish Empire by Louis the Pious in 835. Elsewhere, other dates were observed even later, with the date in Ireland being 20 April. In the early 11th century, the modern date of All Souls' Day was popularized, after Abbot Odilo established it as a day for the monks of Cluny and associated monasteries to pray for the dead.

Allhallowtide, Hallowtide, Allsaintstide, or the Hallowmas season, is the triduum encompassing the Western Christian observances of All Saints' Eve (Halloween), All Saints' Day (All Hallows') and All Souls' Day, which last from October 31 to November 2 annually. Allhallowtide is a "time to remember the dead, including martyrs, saints, and all faithful departed Christians." The present date of Hallowmas (All Saints' Day) and thus also of its vigil (Hallowe'en) was established for Rome perhaps by Pope Gregory III (731-741) and was made of obligation throughout the Frankish Empire by Louis the Pious in 835. Elsewhere, other dates were observed even later, with the date in Ireland being 20 April. In the early 11th century, the modern date of All Souls' Day was popularized, after Abbot Odilo established it as a day for the monks of Cluny and associated monasteries to pray for the dead.