By early March 1862, the new Confederate ironclad CSS Virginia, formerly the wooden steam frigate USS Merrimack, was ready to engage the Union fleet stationed in Hampton Roads. On March 8, Virginia steamed down the Elizabeth River into the roadstead where it sank USS Cumberland and ran USS Congress aground and set it afire. The Virginia retired, intending to sink other ships the next day. That evening, the new Union ironclad USS Monitor arrived to protect the wooden fleet. The Monitor mounted only two guns but they were placed inside a revolutionary revolving turret. The next morning, Monitor and Virginia met in the first engagement of ironclads in history. The two ships fought each other to a standstill but the Virginia retired, unable to inflict serious damage on the Monitor. Both sides claimed victory, but the continued presence of the Monitor neutralized the threat of the Virginia to the Union fleet.