What is "Trick or Treat" also known as what?

In the ninth century, Christianity spread into Celtic lands, where it gradually blended with and supplanted older pagan rites. In 1000 AD the church designated November as All Soul's Day, a time for honoring the dead. Celebrations in England resembled Celtic commemorations of Samhain, complete with bonfires and masquerades.

Poor people would visit the houses of wealthier families and receive pastries called soul cakes in exchange for a promise to pray for the souls of the homeowner's dead relatives. Known as "souling", the practice was later taken up by children, who would go from the front door asking him for gifts such as food, money, etc.

In Scotland and Ireland, young people took part in a tradition called "guising," dressing up in costume and accepting offerings from various households. Rather than pledging to pray for the dead, they would sing a song, recite a poem, tell a joke or perform another sort of "trick" before collecting their treat, which typically consisted of fruits, nuts, or coins.