Where was the trebuchet invented?

The traction trebuchet was first invented between 5th - 4th century BC, when it is first mentioned in a 4th century Chinese text.

The first evidence of a trebuchet is a 4th century text compiled in pre-Imperial China. The Chinese named the later counterweight trebuchet Huihui Pao, where Pao means bombard. The trebuchet spread to the Mediterranean by 6th century AD. The Byzantine Empire began using the trebuchet in the 6th century, and it is mentioned in the Strategicon of Maurice by Emperor Maurice. The counterweight trebuchet is mentioned in the work of the 12th century Byzantine historian Niketas Choniates.