Why is Friday 13 unfortunate?

Today is Friday, April 13th, and all of us have heard that this is viewed as a day that brings bad luck. The date - bearing superstition is said to have its source at the Last Supper, where 13 people were, Jesus Christ and his 12 disciples, one night before being crucified by soldiers [...]
Today is Friday, April 13th, and all of us have heard that this is viewed as a day that brings bad luck.
The date's superstition is said to have its source at the Last Supper, where 13 people were, Jesus Christ and his 12 disciples, one night before being crucified by Roman soldiers on Friday Good Friday.
The 13th is thus bound by Judas Iscaroth, the betrayer of Christ, and is taken as imperfect compared to the 12th, which underscores the number of months of the year.
The alignment of the day and date can also be traced to King Philip IV, who arrested hundreds of Knights of Knights on October 13, 1307, Friday.
Catholic crusaders had been caught under pressure from Pope Clement V on charges by a former member emissary who said the new recruits were ordered to spit on the cross, deny Christ and commit homosexual acts during the initial ceremonies.
The claims since they were found completely unsupported served as an excuse for Philip IV to persecute these people and not pay off their debt for war with England.
It is said that the riders who were burned in the stake in Paris cursed the day and date for everyone and the whole time.
On 2018 we'll have twice Friday on the 13th. One is in April, so today, and another will be in July. The irrational fear of the day is known as “paraskevidvividriaphobia”.
In Spanish-speaking countries and in Greece, it is the Tuesday of the 13th day that scares people. In Italy, it's Friday of the 17th.
Others indicators of bad luck include the stray bad cat, the broken mirror, and so forth. /Periscopi