According to vol. 4 of The Personal Correspondence of Sam Houston, 1852-1863, ed. Madge Thornall Roberts, 2001, p. 86:
"On their 1845 trip to Tennessee, the Houstons had visited Maryville. Margaret probably met Mary when William Wallace organized a barbecue in [Sam's] honor. Inez E. Burns, History of Blount County, Tennessee, from War Trail to Landing Strip (Maryville: Tennessee Historical Commission, 1957), 257."