Unfortunately (or fortunately depending on how you look at it) this is not true. There's more detail in this article www.snopes.com/666th-halloween/ but what it's essentially saying is that there was no moment when Halloween was created - it has evolved over time and is a mixture of different cultures. It talks about the original Pagan festival Samhain and how Christians held a holiday around this time in another attempt to get everyone to convert to Christianity.
That would mean that the first Halloween would have dated from 1349 CE. It's been around a whole lot longer than that. Somebody's having a joke about it.
No that's just a joke.
Not even close. The first All Hallow's Eve preceded the first All Saint's Day or All Hallowed Day when the Catholic church created the day sometime in the 8th century, so that makes it 1200-1300 years ago. It is also based in the Celtic celebration of Samhain. The Celts have been around since the time of Jesus. So actually the celebration and the act of dressing up has been around for about 2000 years.
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