[3] According to historian Roger G. Kennedy in 2000, "Bruin joined the Eleventh Virginia Regiment and served with [Aaron] Burr in Canada, where both were wounded.

Captured during the retreat from Quebec, he contracted smallpox but survived, was released, and reenlisted under General John Sullivan for a campaign against the Iroquois.

Bruin served with the French in their Rhode Island campaign and was with the Virginia Continentals in the siege lines around Yorktown to witness the surrender of Cornwallis.

"[2] According to historian Lawrence Kinnard, "A significant event in the history of Mississippi Valley colonization under Spain was the arrival of Bryan Bruin at New Orleans in 1787.

On March 31, he presented a petition to Governor Miró on behalf of himself and a group of Virginia Catholics for permission to settle in West Florida.

The governor approved the request and granted to each family a tract of land to be located in unoccupied areas fronting upon the Mississippi or any of the creeks or bayous.

Second, as a result of Miró's decision to make liberal grants to Bruin and his associates, it became known that lands might be obtained more easily in Spanish territory than in the United States.

[9] In 1797 he was a signatory, along with Gabriel Benoist, Philander Smith, Daniel Clark, Frederick Kimball, William Ratliff, Roger Dixon, and Isaac Galliard, to a document known as the "Memorial to Congress by Permanent Committee of the Natchez District.

"[10] The group presented themselves as democratically elected representatives of the white land-owning settlers of Mississippi, and signaled that they would rather be associated with the United States than their current Spanish governors, writing that "...to prevent anarchy, and confusion (when his Catholic Majesty may be pleased to withdraw his troops & cause this Country to be given up to the U.S.) prepare a Constitution or form of Govt for this territory which shall in your wisdom appear the best calculated to ensure to the inhabitants of this settlement in its infant State the blessings of peace safety & good order and that the officers of the new government may have the confidence of the people..."[10] They requested that the U.S. Congress allow the continuation of slavery in the Mississippi lands, writing, "Your memorialists beg leave to represent that great part of the labour in this Country is performed by slaves, as in the Southern States, and without which, in their present situation the farms in this District would be but of little more value to the present occupiers than equal quantity of waste land.

"[16] In August 1805 a man called Williams wrote Thomas Jefferson, "I am happy to know there is a probability of our having a Judge, for I do assure you the Territory Suffers very much in its Judicial Charecter—Judge Bruin is Seldom able to attend the Courts.

"[18] Meanwhile, the so-called Scotch settlement of Jefferson County was established after Judge Bruin welcomed a party of Presbyterian immigrants from the Highlands of Scotland.

[9] In March 1808 the Mississippi Territorial Legislature passed a resolution condemning Bruin for having "been much addicted to drunkeness especially during the terms of the Courts, and has frequently appeared on the Bench in such an extreme state of Intoxication as to disqualify him entirely from performing the Solemn and important duties of his Office" resulting in a "manifest injury to the people of this Territory..."[23] The message was passed up the U.S. president who handed it off to the Congress.

[22] Bruin resigned "after thirty-six years of public life" in a letter to U.S. Secretary of State James Madison in October 1808, effective date March 1, 1809.

According to Mississippi historian J. F. H. Claiborne, "Early in January, of the coldest winter ever known here, Colonel Burr, with nine boats, arrived at the mouth of Bayou Pierre, and tied up on the western or Louisiana shore.

He crossed over to the residence of Judge Bruin, (whom he had known in the revolutionary war) and there learned, for the first time, that the Territorial authorities would oppose his descent, though his landing on the Louisiana side would seem to indicate that he apprehended some opposition.

He immediately wrote to Governor Mead, disavowing hostile intentions towards the Territory or the country; that he was en route to the Ouachitta to colonize his lands, and that any attempt to obstruct him would be illegal and might provoke civil war.