* Early forms: Some argue that early cave paintings and pictographs, dating back thousands of years, can be considered precursors to ideographs. These images conveyed meaning but lacked the standardized phonetic representation of later writing systems.
* Mesopotamian cuneiform (around 3200 BCE): While initially pictographic, cuneiform evolved to include ideographic elements. This marked a significant step towards abstract representation of concepts.
* Egyptian hieroglyphs (around 3000 BCE): These hieroglyphs, initially pictographic, also developed ideographic elements alongside phonetic ones.
* Chinese characters (around 1200 BCE): Chinese characters are considered a prime example of a fully developed ideographic writing system. They use a combination of pictograms, ideograms, and phonograms to represent words and concepts.
Therefore, while there's no single "invention" date, the gradual evolution of ideographs can be traced back to the earliest forms of writing, with significant advancements around 3000 BCE in Mesopotamia and Egypt, and a fully realized system in Chinese characters around 1200 BCE.