Republic of Texas passed law against being free and black

Even before slave patrols, the Republic of Texas approved a statute in 1840 dictating that free black people who emigrated to Texas would be given ten days notice, then arrested and forcibly removed from the state. 

if any free persons of color shall emigrate to this Republic, it shall be the duty of the sheriff, or any one of the constables of the county to which such emigration shall be made, to arrest such free person of color, after giving him ten day's notice, and bring him before the Chief Justice of the county, or Judge of the district; and it shall be the duty of the Chief Justice, or Judge of the district, before whom such free person of color may be brought, to receive the bond of such free person of color in the sum of one thousand dollars, with the security of a citizen, to be approved by him, conditioned for the removal of such free person of color out of the limits of the Republic.

There's something they didn't teach us in that 7th grade Texas history class!