13/Historical Note

Historical Note on $13$ (Thirteen)
The number $13$ is traditionally unlucky.

This is apparently based on the fact that there were $13$ people who attended the Last Supper.

It is believed that this superstition originated in the middle ages.

The word triskaidekaphobia means '''fear of the number $13$.

Apart from that, there are several instances of the number $13$ in the mundane world:


 * There are $13$ times $4$ weeks in a year


 * There are $13$ cards in each of the $4$ suits of a pack of cards.