Müller and his wife began working with orphans in 1836. They then kept thirty girls in their own home. Soon after that, they opened three more orphanages. That made the total of children they cared for about 130. In 1845, as they got bigger, Müller decided that they would build another building for around 300 children. In 1849, that home opened. By 1870, more than 2,000 children were being helped in their five homes.