Solid blue with a white star in the middle. It was the original flag of the Republic of Texas.
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I have that flag and fly from time to time, but I’ve always thought it was called the Bonnie Blue Flag as it’s referred to in the song “We Are a Band of Brothers”, an 1861 marching song associated with the Confederate States of America.
Republic of Texas flags
The Burnet Flag was adopted by the Texan Congress on December 10, 1836. ... It consisted of an azure background with a large golden star, inspired by the 1810 “Bonnie Blue Flag” of the Republic of West Florida.
Adopted: January 25, 1839.