Following the secession of Virginia and that state joining the Confederacy, Federal troops marched from Washington into the Arlington region of northern Virginia. The move was intended to forestall any attempt by Virginia militia or Confederate soldiers to seize the capital city of the United States. Over the next seven weeks, forts were constructed along the banks of the Potomac River and at the approaches to each of the three major bridges (Chain Bridge, Long Bridge, and Aqueduct Bridge) connecting Virginia to Washington and Georgetown.