Civil War History
Nothing — from the campaign’s earliest days back in November, to this morning’s attempt to finally bridge the Rappahannock River in Fredericksburg — had gone as planned for the Army of the Potomac. It was mid-afternoon, December 11, 1862. No bridges yet spanned the river. No Federals yet occupied the southern bank. No advance had taken place. http://www.civilwar.org/hallowed-ground-magazine/winter-2012/before-the-slaughter.html
Battle of Fredericksburg
The Federals occupy Fredericksburg
On December 11, Burnside's engineers finally began to assemble the bridges. Confederate snipers in Fredericksburg picked away at the builders, so Yankee artillery began a barrage that reduced to rubble many of the buildings along the river. Three regiments ran the sharpshooters out of the town, and the bridge was completed soon after. By evening on the 11th, the Union army was crossing the Rappahannock. By the next day, the entire army was on the other side and Burnside planned the actual attack.
The Battle of Fredericksburg, which took place on December 13, was an enormous defeat for the Army of the Potomac. Lee lost less than 5,000 men while Burnside lost some 12,600.http://www.history.com/this-day-in-history/federals-occupy-fredericksburg