Why did they execute Louis?

In November 1792, a secret cupboard containing proof of LouisLouisLouis XVI (Louis-Auguste; French pronunciation: ​[lwi sɛːz]; 23 August 1754 – 21 January 1793) was the last King of France before the fall of the monarchy during the French Revolution.https://en.wikipedia.org › wiki › Louis_XVILouis XVI – Wikipedia' counter-revolutionary beliefs and correspondence with foreign powers was discovered in Tuileries Palace. He was brought to trail for treason and executed by guillotine on 21 January 1793.