The attitude of the people of Detroit toward immigrating Negroes had been reflected by the position the people of that section had taken from the time of the earliest settlements. Slavery was prohibited by the Ordinance of 1787. In 1807 there arose a case in which a woman was required to answer for the possession of two slaves. Her contention was that they were slaves on British territory at the time of the surrender of the post in 1796 and that Jay's Treaty assured them to her. Her contention was sustained.[4] A few days later a resident of Canada attempted under this ruling to secure the arrest and return of some mulatto and Indian slaves who had escaped from Canada. The court held that slavery did not exist in Michigan except in the case of slaves in the possession of the British settlers within the Northwest Territory July 11, 1796, and that there was no obligation to give up fugitives from a foreign jurisdiction. An effort was made to take the slaves by force but the agent of the owner was tarred and feathered.[4] Generally speaking, Detroit adhered to this position.[4a] In 1827 there was passed an act providing for the registry of the names of all colored persons, requiring the possession of a certificate showing that they were free and a bond in the sum of $500 for their good behavior.[5] This law was obnoxious to the growing sentiment of freedom in Detroit and was not enforced until the Riot of 1833. This uprising was an attack on the Negroes because a courageous group of them had effected the rescue and escape of one Thornton Blackburn and his wife, who had been arrested by the sheriff as alleged fugitives from Kentucky.[6] The anti-slavery feeling considerably increased thereafter. The Detroit Anti-Slavery Society was formed in 1837, other societies to secure the relief and escape of slaves quickly followed and still another was organized to find employment and purchase homes for refugees.[7] This change of sentiment is further evidenced by the fact that in 1850 it was necessary to call out the three companies of volunteers to quell an incipient riot occasioned by the arrest and attempt to return a runaway slave in accordance with the Fugitive Slave Law. Save the general troubles incident to the draft riots of the Northern cities of 1863,[8] Detroit maintained this benevolent attitude toward Negroes seeking refuge.