A Neolithic city in what is modern-day Turkey was so overcrowded 9,000 years ago that people started trying to kill each other.

Archaeologists working in Çatalhöyük in southern Turkey found that the area was once home to as many as 8,000 people at its peak, making it one of the earliest known cities.

Researchers also found evidence of bashed heads and projectiles, writing that there was a “compelling record of elevated levels of interpersonal violence” that increased as the number of people in the community did.

About one in every four skulls examined by researchers had evidence of having been hit by a small projectile, which they believe were small clay balls – also found on site – flung by slingshots.

Many of the victims were women, with most having been bashed in the head from the rear.

Evidence of overcrowding came from discoveries of the dwellings the people in the settlement lived in: homes were built so close togethe that people had to slip into them from their roofs and interior walls featured residue of human faeces.

The findings were published in the journal Proceedings of the National Academy of Sciences.