This is from a footnote in the Perkins family history on my site:
4. Isaac Johnston who was head of a Robeson County household of one "other free" in 1790 [NC:48], perhaps a descendant of the Johnson Family of Northampton County, Virginia. Joseph Willis was the slave of Agerton Willis of Bladen County who manumitted him and gave him "considerable property." The manumission was approved by the North Carolina General Assembly in 1787 [Byrd, In Full Force and Virtue, 292]. Joseph was a "Molatto" taxable on 320 acres, 1 "white" (free) poll and 2 black (slave) polls in Captain Burn's Bladen County District in 1784, counted as white in 1790, head of a Cheraw District household of 1 male over 16 and 2 females [SC:46], head of a St. Landry Parish household of 13 "other free" and 7 slaves in 1810 [LA:325] and 11 "free colored" and 4 slaves in 1820 [LA:108]. He was buried in Ten Mile Cemetery at Occupy Church in Lower Rapides Parish: Rev. Joseph Willis, 1764-1854, First Baptist preacher of the word in Louisiana west of the Mississippi River [Wise, Sweat Families of the South, 100].