King of Ashkelon in the 8th century BC. He rebelled against the Assyrian king Sennacherib, just like its neighbor the Kingdom of Judah did. Sennacherib started a war against these rebels in 701 BC and destroyed the cities Beth-Dagon, Joppa, Banai-Barqa, and Azjuru that were under Siqia's rule.
References
Sidqia Wikipedia(Text) CC BY-SA