Pictured below is the memorial which marks the mass grave where the remains of ~376 Texas men were buried about two months after their bodies had been burned by the Mexican army. Here's what I've learned about how that happened.

At the Presidio La Bahia on the San Antonio River, just south of Goliad in early 1836, Lt. Col. James Walker Fannin, Jr. commanded a force of almost 400 men. From the Alamo came the urgent appeal from Lt. Col. William Barret Travis for reinforcements before the impending battle with Santa Anna, president of Mexico and commander of the Mexican army. Fannin started the journey but difficulties forced him to return. On 6 March, the Alamo fell and Travis and all his men died under the banner, "Liberty or Death."
On 13 March, Fannin received orders from General Sam Houston to retreat to Victoria. His forces departed on 19 March and that afternoon were attacked by part of the Mexican army (~1200 soldiers) at the Battle of Coleto Creek. Badly outnumbered, cut off from water and supplies, and with many wounded, Fannin negotiated a treaty and surrended the next day. The prisoners were returned to the presidio. On 26 March, orders came from Santa Anna to execute them all as pirates and burn the bodies, and on Palm Sunday, 27 March, it happened.
The men were separated into groups and marched down three different roads. It is said that the Texans thought they were going to get provisions. Then the Mexican soldiers suddenly opened fire and killed most of them on the first shot. Any still living were clubbed, lanced, knifed, or bayoneted to death. Twenty-eight escaped by feigning death and other means. I have seen estimates ranging from 342 to 376 killed.
Fannin was the last to be executed, inside the presidio itself at the courtyard in front of the chapel, along with the wounded. Medical staff and mechanics were spared because they would be useful to the Mexican army. Trenches were dug, and the bodies were piled high and burned.
On 3 June, General Thomas J. Rusk and his troops found the ghastly remains and conducted a proper military funeral, with a general parade, firings, and an eloquent address. "...their murderers sank in death on the prairies of San Jacinto, under the appalling words, "Remember La Bahia," said Gen. Rusk. "...Santa Anna, the mock hero, the black-hearted murderer, is within our grasp [having lost the Battle of Jacinto near today's city of Houston]. Yea, and there he must remain, tortured with the keen pain of corroding conscience. He must oft remember La Bahia, and while the names of those whom he murdered shall soar to the highest pinnacle of fame, his shall sink down into the lowest depths of infamy and disgrace."
Remember the Alamo! Remember Goliad! Remember La Bahia!

