 Complete the following phrase:  In 1863, the unit was transferred to Grand Gulf, Mississippi, a key point on the Mississippi River. After Major General Ulysses S. Grant landed Union infantry at Bruinsburg, Landiss Battery formed part of Confederate defenses at the battles of Port Gibson in early May, after which Landis was promoted and Lieutet John M. Langan took command. Later that month, it took part in the 