Very little is known of the rituals of ancient Samhain because the Church Christianized it – as with many pagan festivals – and what information is available comes from Irish monks who recorded the pre-Christian history of their people as well as other Christian scribes denigrating pagan rites. It seems, however, that the observance included stocking up supplies for the winter, slaughtering cattle, and disposing of the bones in "bone fires" which, in time, came to be known as bonfires. There were gatherings of communities for feasting and drinking while this was going on, but there was also the awareness of the "thin time" of the year and the possibility of otherworldly visitors showing up at the party.
Departed loved ones were expected – and welcomed – and the practice of setting out favorite foods for the dead may have originated as early as 2,000 years ago (though this is unclear), but many other kinds of spirits – some which never had human form – could also appear. Elves, fairies, the "wee folk", sprites, and dark energies were just as likely to pay a visit as those one longed to see again one last time.
Further, there was a very good chance that the spirit of a person one may have wronged would also make an appearance. In order to deceive the spirits, people darkened their faces with ashes from the bonfires (a practice later known as "guising"), and this developed into wearing masks. A living person would recognize the spirit of a loved one and could then reveal themselves but otherwise remain safe from the unwanted attention of darker forces.