What is the title of the first God of War game released for the PlayStation Portable?

Chains of Olympus is the first God of War game released for the PlayStation Portable.

The game launched in 2008 and tells a prequel story set before the original God of War. Kratos is still serving the Olympian gods, and his mission eventually brings him into conflict with Persephone and the Titan Atlas.

Chains of Olympus was designed to preserve the series' fast combat and mythological spectacle on a handheld platform. It was followed on PSP by God of War: Ghost of Sparta, which was released in 2010 and focuses on additional parts of Kratos's past.

God of War: Betrayal was also a portable title, but it was made for mobile phones rather than the PlayStation Portable. Ascension was released for PlayStation 3.