Rosanna Dyer Osterman, Galveston pioneer, Civil War nurse, and philanthropist, was born in Germany on February 26, 1809, and moved with her parents, John M. and Isabella Dyer, to Baltimore, Maryland, at a very young age. Her brothers were Leon Dyer, who served in the Texas Revolution, and Isadore Dyer, a pioneer citizen of Galveston, in whose home the city's first Jewish religious services were held in 1856. On February 23, 1825, in Baltimore she married Joseph Osterman, a silversmith and merchant who was a native of Amsterdam. After suffering financial reverses, Osterman moved to Galveston in 1838 and established a mercantile business trading with all parts of the Republic of Texas and abroad. Rosanna probably arrived in 1839. Osterman's business was so successful that by 1842 he was able to retire; he sold his stock to Isadore Dyer. The Ostermans are credited with having built the first two-story residence in Galveston; this home, at the corner of Broadway and Twenty-fourth streets, became the headquarters of the Young Women's Christian Association in 1921.
Rosanna Osterman's abilities as a nurse were well known in Galveston. During the 1853 yellow fever epidemic she erected a temporary hospital on the family premises in order to nurse the sick and dying. Since there is no record of her ever having received payment for nursing from the Howard Association (see HOWARD ASSOCIATIONS), which was founded in 1854 to aid yellow fever victims, she undoubtedly served as a volunteer nurse during the epidemics that occurred between 1854 and 1866; in her will she bequeathed $1,000 to the Howard Association. Her reputation as a nurse increased during the Civil War years. Though most residents had fled the city by 1862, Mrs. Osterman, by then a childless widow, chose to stay in Galveston and open her home as a hospital, first to Union and then to Confederate soldiers. She won the respect and admiration of the wounded in the Eighth Texas Infantry Regiment , which published a letter of thanks to her in the Galveston News.
Rosanna Osterman died on February 2, 1866, in the explosion of the steamship W. R. Carter on the Mississippi River near Vicksburg, and was buried in the Portuguese Cemetery in New Orleans. She left an estate valued at over $204,000, much of which she bequeathed to charitable organizations. She left the income from the Osterman Building at Twenty-second and the Strand in Galveston to her relatives Isabella Dyer and Hannah Dyer Symonds and to her friend Mary Ann Brown. After their deaths, and in keeping with the provisions of her will, the property was held in trust and the revenue from it applied to the Osterman Widows and Orphans Home Fund. The fund dispensed the revenue to three Galveston orphanages and the Letitia Rosenberg Woman's Home between 1905 and 1951, when the property was sold and the proceeds divided among the four institutions. Other provisions of her will included the bequest of $5,000 toward a synagogue in Galveston (Temple B'nai Israel, Galveston, was dedicated in 1871); $2,500 toward a synagogue in Houston (the Franklin Avenue Temple of Congregation Beth Israel, Houston, was dedicated in 1871); $1,000 each for the benefit of a Galveston and a Houston Hebrew benevolent society (the Galveston Hebrew Benevolent Society was established on May 1, 1866); $1,000 to found a school for poor Jewish children in Galveston and Houston; $1,000 for the expansion and upkeep of the Galveston Hebrew Cemetery; and $1,000 for a Galveston Sailor's Home. The remainder of her bequests went to Jewish charitable organizations in New Orleans, Cincinnati, New York, and Philadelphia and to individual relatives and friends.