Aaron Burr Jr. (February 6, 1756 – September 14, 1836) was an American politician, businessman, lawyer, and Founding Father who served as the third vice president of the United States from 1801 to 1805 during Thomas Jefferson's first presidential term.

After studying theology at Princeton University, he began his career as a lawyer before joining the Continental Army as an officer in the American Revolutionary War in 1775.

After leaving military service in 1779, Burr practiced law in New York City, where he became a leading politician and helped form the new Jeffersonian Democratic-Republican Party.

[8][9] In 1775, news reached Litchfield of the clashes with British troops at Lexington and Concord, and Burr put his studies on hold to enlist in the Continental Army.

[10] During the American Revolutionary War, Burr took part in Colonel Benedict Arnold's expedition to Quebec, an arduous trek of more than 300 miles (480 km) through the northern frontier of the Province of Massachusetts Bay (now Maine).

[11] In the spring of 1776, Burr's stepbrother Matthias Ogden helped him to secure a position with George Washington's staff in Manhattan, but he quit on June 26 to be on the battlefield.

[16] In late 1776, Burr attempted to secure Washington's approval to retake fortifications held by the British on Staten Island, citing his deep familiarity with the area.

Later that year, Burr commanded a small contingent during the harsh winter encampment at Valley Forge, guarding "the Gulph," an isolated pass that controlled one approach to the camp.

[21] In January 1779, Burr was assigned to Westchester County, New York, in command of Malcolm's Regiment, a region between the British post at Kingsbridge and that of the Americans about 15 miles (24 km) to the north.

This district was part of the more significant command of General Alexander McDougall, and there was much turbulence and plundering by lawless bands of civilians and by raiding parties of ill-disciplined soldiers from both armies.

[47] In the 1800 presidential election, Burr combined the political influence of the Manhattan Company with party campaign innovations to deliver New York's support for Jefferson.

In 2011, however, historian Thomas Baker discovered a previously unknown letter from William P. Van Ness to Edward Livingston, two leading Democratic-Republicans in New York.

[67] Historian William Weir speculated that Hamilton might have been undone by his machinations: secretly setting his pistol's trigger to require only a half-pound of pressure as opposed to the usual ten pounds.

[75] After Burr left the vice presidency at the end of his term in 1805, he journeyed to the western frontier, areas west of the Allegheny Mountains and down the Ohio River Valley, eventually reaching the lands acquired in the Louisiana Purchase.

Starting in Pittsburgh and then proceeding to Beaver, Pennsylvania, and Wheeling, Virginia, and onward he drummed up support for his planned settlement, whose purpose and status was unclear.

[76] Burr's most important contact was General James Wilkinson, Commander-in-Chief of the United States Army at New Orleans, and governor of the Louisiana Territory.

In case of a war declaration, Andrew Jackson, at this point the commander of the Tennessee militia, stood ready to help Burr, who would be in a position to join in immediately.

Burr's expedition of about eighty men carried modest arms for hunting, and no war materiel was ever revealed, even when Blennerhassett Island was seized by the Ohio militia.

[78] The aim of his "conspiracy," Burr always avowed, was that if he settled there with a large group of armed "farmers" and war broke out, he would have a force with which to fight and claim land for himself, thus recouping his fortunes.

[82] Burr's secret correspondence with Anthony Merry and the Marquis of Casa Yrujo, the British and Spanish ministers at Washington, was eventually revealed.

If Burr intended to found a dynasty in what would have become former Mexican territory,[55] this was a misdemeanor, based on the Neutrality Act of 1794, which Congress passed to block filibuster expeditions against U.S. neighbors, such as those of George Rogers Clark and William Blount.

The only physical evidence presented to the grand jury was Wilkinson's so-called letter from Burr, which proposed the idea of stealing land in the Louisiana Purchase.

He died on Staten Island in the village of Port Richmond, in a boarding house that later became known as the St. James Hotel[95] on September 14, 1836, at the age of 80, the same day the divorce was officially completed.

[26] When they returned in 1783 to become citizens of the United States,[26] Burr acted as a father to them: he assumed responsibility for their education, gave both of them clerkships in his law office and frequently was accompanied by one of them as an assistant when he traveled on business.

[102] Burr opened his home to them, allowing Madame Senat to tutor private students there along with his daughter, and Nathalie became a companion and close friend to Theodosia.

[citation needed] In addition to cultivating relationships with women in his social circles, his journals indicate that he was a frequent patron of prostitutes during his travels in Europe; he recorded brief notes of dozens of such encounters, and the amounts he paid.

[126] Burr also fought against anti-immigrant sentiment, led by Hamilton's Federalist party, which suggested that anyone without English heritage was a second-class citizen and even challenged the rights of non-Anglos to hold office.

[129] Gordon S. Wood, a leading scholar of the revolutionary period, holds that it was Burr's character that put him at odds with the rest of the Founding Fathers, especially Madison, Jefferson and Hamilton.

[130] Although Burr is often remembered primarily for his duel with Hamilton, his establishment of guides and rules for the first impeachment trial set a high bar for behavior and procedures in the Senate chamber, many of which are followed today.

Historian Nancy Isenberg, seeking to explain Burr's negative image in modern times, wrote that his portrayal as a villain is actually the result of a smear campaign invented by his political enemies centuries ago, and then disseminated in newspapers, pamphlets and personal letters during and after his lifetime.