Early mortars like the Pumhart von Steyr were big and heavy. They were also difficult to move around. An early mortar that could be moved easily was invented by Baron (Siege of Grave, 1673). At the Siege of Vicksburg, General Ulysses S. Grant reported making mortars "by taking logs of the toughest wood that could be found, boring them out for six or twelve-pound shells and binding them with strong iron bands. These answered as coehorns, and shells were successfully thrown from them into the trenches of the enemy."