Around the year 100, the Roman historian Tacitus wrote:
In 64 there was a big fire: half of Rome burned down.
Soon it was told that Emperor Nero had ordered the fire to be started because he needed space for a new palace.
That is why Nero blamed the Christians. He had them severely punished.
For example, they were given beast skins to be torn apart by wild dogs, or crucified, or killed by fire: at the end of the day they were lit to serve as streetlights.