Jeremiah Brown, naval officer of the Republic of Texas, was given command of the schooner-of-war Invincible on March 12, 1836. Although Commodore Charles E. Hawkins is said to have placed Brown in irons immediately after taking command of the Texas fleet at Matagorda, he nevertheless retained command of what was reckoned the finest ship in the Texas Navy. As captain of the Invincible, Brown was dispatched by Hawkins to patrol off Matamoros to prevent Mexican reinforcements and supplies from reaching Antonio López de Santa Anna's army in Texas and in particular to engage or drive off the Mexican ship Moctezuma. Brown encountered and engaged the Mexican brig-of-war, then rechristened Bravo, at the mouth of the Rio Grande on April 3, 1836. The Bravo, fighting without her rudder, was run aground and wrecked by a broadside from the Invincible. Later that same day Brown captured the American-owned brig Pocket, out of New Orleans, en route from Matamoros to Santa Anna's army in Texas with a contraband cargo of flour, rice, lard, biscuit, and 300 kegs of powder. Brown arrived on April 8 with his prize at Galveston, and there he learned from captured documents that Santa Anna had plans to capture all Texas ports and to station 1,000 men on Galveston Island. Thus forewarned, the Texas government hastily fortified the island. The provisions captured aboard the Pocket ultimately were consigned to Sam Houston's army. Brown, then aboard the Invincible at Galveston, was the first Texas naval officer to receive word of the Texas victory at San Jacinto. Overjoyed, he began firing the midship gun until he reflected, "Hold on boys or old Hawkins will put me in irons again."
The Invincible sailed to New Orleans to refit, and the crew was charged with piracy. Forty-six of the crew members left the city abruptly to avoid arrest, leaving Brown ashore. When his ship was returned to New Orleans on May 1, under the escort of the United States ship Warren, however, Brown surrendered to federal authorities on May 20. On the same day he was released on bail provided by Thomas Toby, a merchant friendly to the Texas cause, and he was later acquitted of the charge. After being rearrested on the same charge, Brown was again aided by Toby, who purchased the Pocket and paid all of the claims against the crew of the Invincible. Brown was then personally sued by the Pocket's insurer for the cost of its cargo, but no record of the suit's outcome has come to light. The United States government concluded a convention with Texas, whereby Texas paid $11,750 for damage claims filed by passengers and crew of the Pocket, plus $705 in interest.
The Invincible was released from New Orleans and went back on patrol in the Gulf. On June 1 she took aboard the captured Mexican general Santa Anna and was at first ordered to sail with him to Veracruz. On June 5, however, volunteers under Gen. Thomas J. Green forbade the Invincible to sail. Thus relieved of that responsibility, Brown and his ship rode at anchor off Velasco until July 4, when they came to the aid of the Brutus, menaced off Matagorda by the powerful Vencedor del Álamo, and succeeded in frightening away the Mexican ship and chasing it as far as Veracruz. After blockading the harbor for several days, Brown returned to New Orleans, where his ship took on passengers Branch T. Archer and William H. Wharton and sailed on July 13 for Galveston. Brown then returned to Velasco and received orders to blockade Matamoros. The Invincible was ordered to New York for refitting on August 4 and arrived there in September. Brown returned his ship to Galveston on March 14, 1837. That month he was relieved of duty, and the Invincible was placed under the command of Commodore H. L. Thompson by order of the new president, Sam Houston. Jeremiah Brown was the elder brother of William S. Brown, also a captain in the Texas Navy.