Katy Holland McDowell Treadwell Cobb. In 1822, at the age of seven, Katy Holland migrated to Texas with her parents as a member of Stephen F. Austin's "Old 300" Colony. Her life reflects the harshness of frontier life in Texas. Twice widowed before her marriage to William Cobb in the 1840s, she was the mother of five children. Her first husband, Mill McDowell, was also a member of Austin's Colony, and a cousin, Tapley Holland, was killed at the Alamo. #8567