The battle of Lade was the second of two naval battles fought by Philip V of Macedonia during 201 BC. Philip had begun to construct a war fleet during the First Macedonian War against Rome, but the fleet was not completed until after the end of the war in 205 BC. Once the fleet was ready, in 202 BC, Philip went onto the offensive, attacking a series of independent cities around the Aegean. Rhodes and Attalus of Pergamum were both directly threatened by Philip’s actions, and were soon drawn into a war against him.
The exact order of events during 201 is unclear. Philip was active in Asia Minor, at some point attacking the city of Pergamum. One of his targets during this period was the island of Chios, sixty miles to the south west of Pergamum. A large naval battle followed (battle of Chios) in which the Rhodians were successful, but Attalus was defeated, leaving Philip free to complete the conquest of Chios. In the aftermath of this battle Attalus returned to Pergamum, while the Rhodian fleet moved south, taking up a new position at Lade, off Miletus.
Philip followed the Rhodians, and attacked them at Lade. The losses he had suffered at Chios meant that the Macedonian fleet was not powerful enough to inflict a crushing defeat on the Rhodian fleet, but he still won a victory. The Rhodian fleet then retreated further south, while Philip returned to his campaign in Asia Minor.