Horace (Horatio, Horacio) Arlington (Alex, Alexander) Alsbury (Alsberry, Allsbury; variant spellings occur in the surname of related Alsburys), possibly a native of Hopkinsville, Kentucky, came to Texas as one of Stephen F. Austin's Old Three Hundred. With two of his brothers, James Harvey and Charles Grundison Alsbury, he received title to a league and a half of land now in Brazoria County on August 3, 1824. Although he called himself a doctor, it is not known where he studied medicine. He rode horseback across the Rio Grande between Mexico and Texas numerous times. He wrote voluminously to important persons in the Texas government and volunteered for numerous military activities. In January 1834 Stephen F. Austin wrote from Monterrey that he was sending by "Mr. Allsbury," probably Horace Alsbury, two portrait miniatures of himself to his Texas kin. In late August 1835, after perhaps being at the legislature of Coahuila and Texas in Monclova, Alsbury published a handbill in Columbia, "To The People Of Texas," warning of Antonio López de Santa Anna's plans to drive Anglo-Americans from Texas. In the siege of Bexar (November-December 1835) he was a member of Capt. John York's Company. In early 1836 Alsbury married Mrs. Juana Navarro Pérez, daughter of José Ángel Navarro, a Santa Anna loyalist of Bexar. She remained in the Alamo during the siege and final assault by Mexican forces (see ALSBURY, JUANA NAVARRO). Alsbury rode from the Alamo as one of the messengers on February 23, during the first hours after Santa Anna captured Bexar. On March 1 he possibly accompanied the thirty-two Gonzales volunteers on their way to the Alamo, and on March 3 he was in Gonzales with other Texas volunteers after failing to contact James W. Fannin's division expected to reinforce the Alamo.
Alsbury was a member of Henry W. Karnes's company at San Jacinto and was one of the 154 Masons to take part in the fighting. After the battle he joined in the surveillance of Mexican troops retreating from San Jacinto toward La Bahía and Mexico. He returned to Bexar in May 1836 and took his wife and her young son away from the devastated town to Calavero Ranch, on the Goliad road.
He received a military donation and bounties for his service at San Jacinto. The Congress of the Republic of Texas allowed him payment for service as major of the infantry and as interpreter for the post of Bexar, 1835 and 1836. He secured a land grant south of San Antonio near the site of present Von Ormy. In 1837 he successfully bid for office of tax assessor for Bexar County, which he may have held for some time before John W. Smith assumed the position. In early 1838 Alsbury and Joseph Baker, as Indian agents of the republic, led a group of men from Bexar and met with the Comanches on a peace mission on the Pedernales. They barely escaped with their lives.
In late 1838 Alsbury wrote from San Antonio regarding the favorable business in South Texas with self-proclaimed Federalist traders from Mexico. In late 1839 and early 1840 Alsbury served as commander of Federalist leader Antonio Canales's bodyguard along the Rio Grande during the running battles of Mexican general Mariano Arista's forces against Canales and Samuel W. Jordan's movement to establish the Republic of the Rio Grande. During desperate fighting, Alsbury and his command, fleeing for their lives, escaped into Texas.
In 1839 Alsbury joined other San Antonio citizens to ask for government protection of their lives and those of their families against Indian and Mexican incursions. In early September 1842 he was among the Texans captured by Mexican general Adrián Woll and marched to Mexico's Perote Prison, where he remained until his release on March 24, 1844. According to Juana Alsbury her husband accompanied the American army across the Rio Grande in 1846 during the Mexican War and was killed somewhere between Camargo and Saltillo in June 1847.