Here's what we know:
* Early forms of writing: The earliest known Chinese writing dates back to the Shang Dynasty (c. 1600–1046 BCE), with oracle bone script.
* Development: The writing system continued to develop and evolve over the centuries, leading to the Classical Chinese used during the Han Dynasty (206 BCE - 220 CE) and later.
* Modern Chinese: The written language we know today, with its simplified characters, emerged in the 20th century, though the spoken language has also been evolving for millennia.
Therefore, it's impossible to pinpoint a single "invention" date for Chinese. It's a complex and fascinating story of linguistic and cultural development spanning millennia.