Union forces acted this week in 1863 in a coordinated onslaught against Confederates holding Port Hudson, La., bidding to dislodge them while Ulysses S. Grant ratcheted up his offensive against the heavily fortified city of Vicksburg, further up the Mississippi River. The Union on May 27, 1863, unleashed assaults on Confederate fortifications at Port Hudson, only to be pushed back. Federal fighters then lapsed into a siege at Port Hudson that would last for several weeks before Union fighters would again try - and fail - with another assault in mid-June. It wouldn't be until early July 1863 when Grant's Union fighters had forced the surrender of the Confederate garrison at Vicksburg, Miss., before Port Hudson would capitulate. The fighting in Louisiana and Mississippi marked a new chapter in the war as Grant sought would assert Union control over the entire Mississippi River through the Deep South to federally held New Orleans.