Final answer:
Ramses II's most famous military campaign was against the Hittites, where he attempted to retake the city of Qadesh in Syria.
Step-by-step explanation:
The most famous military campaign that Ramses II fought was against the Hittites. During his reign, Ramses II fought several wars with the Hittites in Syria. In an attempt to restore Egyptian influence in Syria, Ramses II led an army into Syria to retake the city of Qadesh. While the attempt to recapture Qadesh failed, Ramses II claimed the campaign was a success.