Historians say variously that the Middle Ages ended with the fall of Constantinople, in 1453; with the discovery of America, in 1492; or with the beginning of the Reformation, in 1517. A New Empire In The West. The Early Middle Ages, 500-1000.
Halloween's Origins. The word Halloween is derived from the term, All Hallows Eve, which occurred on Oct. 31. All Saints Day or All Hallows Day was the next Day, Nov. 1st. Therefore, Halloween is the eve of All Saints Day. Some say that the origins of Halloween can be traced back to ancient Ireland and Scotland around the time of Christ. On Oct. 31st the Celts celebrated the day because it was when animal herders would move their animals into barns and pens and prepare to ride out the winter. This was also the time of the crop harvests.
The word Halloween or Hallowe'en dates to about 1745 and is of Christian origin. The word Halloween means  hallowed evening or holy evening. It comes from a Scottish term for All Hallows' Eve (the evening before All Hallows' Day). In Scots, the word eve is even, and this is contracted to e'en or een. Over time, (All) Hallow(s) E(v)en evolved into Halloween.