ChristmasDayisaholidayobservedgenerallyonDecember25tocommemoratethebirthofJesus,thecentralfigureofChristianity.ThedateisnotknowntobetheactualbirthdayofJesus,andmayhaveinitiallybeenchosentocorrespondwitheitherthedayexactlyninemonthsaftersomeearlyChristiansbelievedJesushadbeenconceived,thedateofthewintersolsticeontheancientRomancalendar,oroneofvariousancientwinterfestivals.ChristmasiscentraltotheChristmasandholidayseason,andinChristianitymarksthebeginningofthelargerseasonofChristmastide,whichlaststwelvedays.

　　AlthoughnominallyaChristianholiday,Christmasisalsowidelycelebratedbymanynon-Christians,andmanyofitspopularcelebratorycustomshavepre-Christianorsecularthemesandorigins.Popularmoderncustomsoftheholidayincludegift-giving,music,anexchangeofgreetingcards,churchcelebrations,aspecialmeal,andthedisplayofvariousdecorations;includingChristmastrees,lights,garlands,mistletoe,nativityscenes,andholly.Inaddition,severalsimilarmythologicalfigures,knownasSaintNicholas,FatherChristmasandSantaClausamongothernames,areassociatedwithbringinggiftstochildrenduringtheChristmasseason.

　　Becausegift-givingandmanyotheraspectsoftheChristmasfestivalinvolveheightenedeconomicactivityamongbothChristiansandnon-Christians,theholidayhasbecomeasignificanteventandakeysalesperiodforretailersandbusinesses.TheeconomicimpactofChristmasisafactorthathasgrownsteadilyoverthepastfewcenturiesinmanyregionsoftheworld.