Secretary of Treasury Salmon P. Chase believed Nelson's actions had kept Kentucky loyal and promoted him to brigadier general in September 1861.

Nelson's 4th Division bore the brunt of heavy fighting at the Battle of Shiloh and took part in the Siege of Corinth; he was the first man to enter the town.

It was there that General Jefferson C. Davis, still officially on sick leave, reported to Nelson, who was dissatisfied with his performance and insulted him in front of witnesses.

[1][2] Two years later, Nelson's preparatory training at the Vermont military school concluded when Representative Garrett Davis secured an appointment for him to become a midshipman in the US Navy.

[6][7] On July 11, 1846, Nelson became a passed midshipman,[8] and the next October, he reported for duty aboard the USS Raritan, the flagship for the Home Squadron in the Gulf of Mexico.

[9] In the summer of 1849, he joined the Mediterranean Squadron, and on September 1, 1851, he was acting lieutenant of the USS Mississippi when exiled Hungarian revolutionary Louis Kossuth boarded the vessel to come to the United States.

[10] The second day after the inauguration of Abraham Lincoln, US Navy Lieutenant William Nelson walked into the Executive Mansion with the peculiar manner of Kentuckians that said: "Here I am; if you don't like me, the worse for you.

He had a natural affinity for the Southern way of life, and Lincoln could see that subversive elements might want to court such a "warm hearted, handsome," and "aristocratic" individual who gave the impression of someone who was apt to "cast his lot" with slaveholders.

[13] At the request of Lincoln, Nelson measured the political currents of his native state and returned to the Executive Mansion on May 3, 1861, with "his plan for furnishing arms to the Kentucky Unionists."

Nelson was to work out details for a distribution of arms in Kentucky with Joshua Fry Speed in Louisville, and as he headed off, Secretary of War Simon Cameron released 5,000 ancient Prussian flintlocks that had been converted into percussion cap rifles to shift the balance of power to the Union Home Guard.

The latter town was conveniently located at the south end of the turnpike in Garrard County and was at the head of the Wilderness Road, 65 mi north of the Cumberland Gap at the old inn at Bryant Springs, the first headquarters, and it was agreed the leaders would raise thirty companies of infantry and five of cavalry.

On November 8, Confederate troops, under Captain Andrew Jackson May, fought a delaying action against Nelson at the Battle of Ivy Mountain.

Early the next morning, Nelson's northern prong, under Colonel Joshua W. Sill, arrived at the town, which marked the end of the Big Sandy expedition.

It was there that Brigadier General Nelson was approached by William Driver, a sea captain who had retired to Nashville and remained loyal to the Union.

Nelson arrived at Savannah on Saturday, April 5, 1862, and at dawn the following morning, the enemy assaulted Federal troops below Shiloh Church.

Fresh troops under Nelson reached the Union line around 5:30 PM, and reinforced Grant's left flank and helped repulse the final two Confederate charges of the day.

Those men had no love for the harsh ways of "Big Buster," but they genuinely valued his willingness to chastise officers openly who shirked their responsibilities.

Nelson was therefore the first to enter the city on May 30, 1862,[citation needed] and he immediately became embroiled in a disgraceful fight with Brigadier General John Pope over who deserved credit for occupying the abandoned town.

Several weeks later, Nelson was caught up in an ill-fated advance against Chattanooga that put him in the unenviable position of going against enemy cavalry with overburdened infantry.

Three hundred miles of railway lines lay between Louisville and Chattanooga, and Confederate forces were making constant work in tearing up the tracks.

When Nelson arrived in Louisville, he found Major General Horatio G. Wright had been sent by Lincoln to take control, which put Buell second in command.

[26] Further losses at the battle occurred with the capture of Brigadier General Mahlon D. Manson and the wounding of Nelson, injured in the neck, who retreated to Louisville to prepare for the presumed assault.

I find myself compelled by physical weakness and exhaustion to ask... for a few weeks respite from duty...."[28] On August 12, 1862, the Army of Mississippi issued Rosecrans's response in Special Order No.

General James B. Fry, described as a close friend of Davis, was present and would later write an account of the events surrounding Nelson's death.

Nelson turned toward the Adjutant-General and said, "Captain, if General Davis does not leave the city by nine o'clock tonight, give instructions to the Provost-Marshal to see that he shall be put across the Ohio River.

[34] Davis arrived in Louisville in the afternoon on Sunday, September 28, and reported to the Galt House early the next morning, at breakfast time.

His trial by a court-martial or military commission should take place immediately, but I can't spare officers from the army now in motion to compose a court.

I was satisfied that Davis acted purely on the defensive in the unfortunate affair, and I presumed that Buell held very similar views, as he took no action in the matter after placing him in arrest."

Early the next day, Buell started advancing the Army of the Ohio against Confederate Major Generals Edmund Kirby Smith and Braxton Bragg.

On June 12, 1863, authorities honored the victim by naming the new supply depot in Jessamine County, Kentucky, Camp Nelson.