This week 150 years ago in the Civil War, Union forces besiege New Madrid, Mo., seeking to gain control at this juncture of the Mississippi River.

The attackers march overland, arriving near New Madrid on March 3, 1862. The siege will last several days and only after heavy Union guns are brought in will the Confederate defenders retreat. Union forces will occupy the recently deserted city on March 14, 1862.

Now the fight for control of the Mississippi will shift to other areas of the river — with The Associated Press reporting the Confederates “have a very strong position” on Island No. 10, not far from New Madrid.

This week also sees a new era of naval warfare open when ironclad ships — vessels sheathed in stout armor — clash near Hampton Roads, Va. On March 8, 1862, the Confederate ironclad CSS Virginia attacks a squadron of Union naval forces at Hampton Roads, destroying two ships and stranding a third, the Minnesota. The Monitor arrives the following day and the battle is on.

The two ironclads circle and fire at each other for several hours that morning, neither sinking or seriously damaging the other. At midday, the Monitor attempts to ram the Virginia but a steering malfunction leads the Monitor to miss the Virginia’s fantail. As the Monitor passes the stern of the Virginia, the Monitor’s pilothouse is hit by a shell and breaks off action. Soon the Virginia retreats to the nearby Elizabeth River, unable to finish off the damaged Minnesota. The outcome is indecisive.

Union forces still dominate Hampton Roads and the Confederates still control several rivers and nearby Norfolk, Va. But history has been made. Though French and British fleets had begun building ironclad ships by the time the American conflict opened, the new naval technology hadn’t been tried in battle until now.