Allhallowtide in the context of Basilica of Santa Maria Novella

Halloween, also known as All Hallows' Eve, or All Saints' Eve, is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. It is at the beginning of the observance of Allhallowtide, the time in the Christian liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed. In popular culture, Halloween has become a celebration of horror and is associated with the macabre and the supernatural.

One theory holds that many Halloween traditions were influenced by Celtic harvest festivals, particularly the Gaelic festival Samhain, which are believed to have pagan roots. Some theories go further and suggest that Samhain may have been Christianized as All Hallows' Day, along with its eve, by the Church. Other academics say Halloween began independently as a Christian holiday, being the vigil of All Hallows' Day. Celebrated in Ireland and Scotland for centuries, Irish and Scottish immigrants brought many Halloween customs to North America in the 19th century, and then through American influence various Halloween customs spread to other countries by the late 20th and early 21st century.

The Day of the Dead (Spanish: Día de (los) Muertos) is a holiday traditionally celebrated on November 1 and 2, though other days, such as October 31 or November 6, may be included depending on the locality. The multi-day holiday involves family and friends gathering to pay respects and remember friends and family members who have died. These celebrations can take a humorous tone, as celebrants remember amusing events and anecdotes about the departed. It is widely observed in Mexico, where it largely developed, and is also observed in other places, especially by people of Mexican heritage. The observance falls during the Christian period of Allhallowtide. Some argue that there are Indigenous Mexican or ancient Aztec influences that account for the custom, though others see it as a local expression of the Allhallowtide season that was brought to the region by the Spanish; the Day of the Dead has become a way to remember those forebears of Mexican culture. The Day of the Dead is largely seen as having a festive characteristic.

Traditions connected with the holiday include honoring the deceased using calaveras and marigold flowers known as cempazúchitl, building home altars called ofrendas with the favorite foods and beverages of the departed, and visiting graves with these items as gifts for the deceased. The celebration is not solely focused on the dead, as it is also common to give gifts to friends such as candy sugar skulls, to share traditional pan de muerto with family and friends, and to write light-hearted and often irreverent verses in the form of mock epitaphs dedicated to living friends and acquaintances, a literary form known as calaveras literarias.

All Souls' Day, also called The Commemoration of All the Faithful Departed, is a day of prayer and remembrance for the faithful departed, observed by Christians on 2 November. In Western Christianity, including Roman Catholicism and certain parts of Lutheranism and Anglicanism, All Souls' Day is the third day of Allhallowtide, after All Saints' Day (1 November) and All Hallows' Eve (31 October). Before the standardization of Western Christian observance on 2 November by St. Odilo of Cluny in the 10th century, many Roman Catholic congregations celebrated All Souls' Day on various dates during the Easter season as it is still observed in the Eastern Orthodox Church, the Eastern Catholic churches and the Eastern Lutheran churches. Churches of the East Syriac Rite (Assyrian Church of the East, Ancient Church of the East, Syro-Malabar Catholic Church, Chaldean Catholic Church, Syriac Catholic Church) commemorate all the faithful departed on the Friday before Lent. As with other days of the Allhallowtide season, popular practices for All Souls' Day include attending Mass offered for the souls of the faithful departed, as well as Christian families visiting graveyards in order to pray and decorate their family graves with garlands, flowers, candles and incense. Given that many Christian cemeteries are interdenominational in nature, All Souls' Day observances often have an ecumenical dimension, with believers from various Christian denominations praying together and cooperating to adorn graves.

Halloween, is a celebration observed in many countries on 31 October, the eve of the Western Christian feast of All Hallows' Day. It is at the beginning of the observance of Allhallowtide, the time in the Christian liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed. In popular culture, Halloween has become a celebration of horror and is associated with the macabre and the supernatural.

One theory holds that many Halloween traditions were influenced by Celtic harvest festivals, particularly the Gaelic festival Samhain, which are believed to have pagan roots. Some theories go further and suggest that Samhain may have been Christianized as All Hallows' Day, along with its eve, by the Church. Other academics say Halloween began independently as a Christian holiday, being the vigil of All Hallows' Day. Celebrated in Ireland and Scotland for centuries, Irish and Scottish immigrants brought many Halloween customs to North America in the 19th century, and then through American influence various Halloween customs spread to other countries by the late 20th and early 21st century.

The International Day of Prayer for the Persecuted Church (often abbreviated as IDOP) is an observance within the Christian calendar in which congregations pray for Christians who are persecuted for their faith. It falls on the first Sunday of November, within the liturgical period of Allhallowtide, which is dedicated to remembering the martyrs and saints of Christianity. The International Day of Prayer for the Persecuted Church is observed by many Christian denominations, with over 100,000 congregations honoring the holiday worldwide. Congregations focus on "praying for individuals, families, churches, or countries where Christians are facing hard situations." Additionally, many congregations donate funds from their collection of tithes and offerings on the International Day of Prayer for the Persecuted Church to NGOs that support human rights of persecuted Christians, such as Voice of the Martyrs, International Christian Concern, and Open Doors.