On November 9, 1799, Telemaque won $1500 in a city lottery. At the age of 32, he bought his freedom for $600 from Vesey. He took the surname Vesey and the given name of 'Denmark,' after the nation ruling his birthplace of St. Thomas. Denmark Vesey began working as an independent carpenter and built up his own business. By this time he had married Beck, an enslaved woman. Their children were born into slavery under the principle of partus sequitur ventrem, by which children of a slave mother took her status. Vesey worked to gain freedom for his family; he tried to buy his wife but her master would not sell her. This meant their future children would also be born into slavery. Along with many other slaves, Vesey had belonged to the Second Presbyterian church, and chafed against its restrictions on black members. In 1818 he was among founders of a congregation on what was known as the "Bethel circuit" of the African Methodist Episcopal Church . This had been organized in Philadelphia, Pennsylvania in 1816 as the first independent black denomination in the United States. The AME Church in Charleston was supported by leading white clergy. In 1818 white authorities briefly ordered the church closed, for violating slave code rules that prohibited black congregations from holding worship services after sunset. The church attracted 1848 members, making it the second largest AME church in the nation. City officials always worried about slaves in groups; they closed the church again for a time in 1821, as the City Council warned that its classes were becoming a "school for slaves" . Vesey was reported as a leader in the congregation, drawing from the Bible to project hope for freedom.

Based on the above article, answer a question. Why would Vesey's children be born into slavery?
tried to buy his wife