When was Spanish invented?

Spanish wasn't "invented" in the way a new technology might be. It evolved over centuries from Vulgar Latin, the language spoken by the common people in the Roman Empire.

Here's a simplified timeline:

* 711 AD: The Muslim conquest of the Iberian Peninsula begins, leading to a period of Arabic influence in the region.

* 8th-15th centuries: The languages spoken in the northern part of the Iberian Peninsula, which had not been conquered by the Moors, slowly diverged from Vulgar Latin, eventually becoming Castilian, the predecessor to modern Spanish.

* 15th-16th centuries: Castilian became the dominant language of Spain, as the kingdoms in the north eventually conquered the rest of the peninsula.

* 16th-19th centuries: Spanish spread throughout the Americas, as a result of the Spanish conquest.

Therefore, there's no single date for the "invention" of Spanish. It's a language with a long and complex history, evolving over many centuries.