On Friday 13 since antiquity is taken as a bad omen, it's like a day of terror or where you know something bad will happen, this myth has to do with several things that relate to damn the day and has nothing to do with Tuesday 13 which is another example diferente.Mitos myth of Friday 13
It is said that during the reign of Philip IV in France, happened on Friday, October 13, 1307 that took all the Templars met for there to be sentenced to the stake for acts of heresy and among other things, spitting and urinating on the cross, nothing was said made sense, since these men had given their lives for the church, but by this time people were super-wealthy and even the King of France owed money, so say sent to kill this way, everything was under the command and permission of the pope who had at the time, and this ranked as the most unfair, they say the date was exposed on Friday 13 and that something bad might happen, as several Templars escaped from this inquisition and continued with myth.
On the other hand we can say that the myth is even further behind because the 13th is a benchmark for many things such as can say that is the chapter of the Bible that refers to Antichrist, or at the Last Supper of Jesus there were 13 guests, in Norse mythology was a dinner and the evil Loki was the guest number 13, then also it appears in the Cavala where it says that there are 13 evil spirits, commented that in other religions is the god of death and the tarot is also the letter of death.