Xerxes retreated to Asia with much of his army, leaving Mardonius to complete the conquest of Greece. However, the following year, the remainder of the Persian army was decisively beaten at the Battle of Plataea and the Persian navy at the Battle of Mycale. The Persians made no further attempts to conquer the Greek mainland. These battles of Salamis and Plataea thus mark a turning point in the course of the Greco-Persian wars as a whole; from then onward, the Greek "poleis" would take the offensive.