beginning circa 1697, portuguese colonists in brazil began using the labor of enslaved africans to build the road. this was shortly after gold, diamonds, and other precious minerals were discovered in the state of minas gerais. the road's purpose was to facilitate the movement of those minerals from the interior to the coast and thence to lisbon. the original road—"caminho velho"—began in paraty and went north through the towns of são joão del-rey, tiradentes, coronel xavier chaves, congonhas, itatiaia and, ultimately, vila rica, today's ouro preto. later, the distance to ouro preto was shortened by the "caminho novo", which started from rio de janeiro. the road was extended northward through mariana, catas altas, santa bárbara, barão de cocais, ipoema, conceição do mato dentro, serro, são gonçalo do rio das pedras, and, at the northernmost point, diamantina. the length of both roads combined is about .