The ancient Egyptians are known for their mummies of people and animals. They were part of the complicated religious rituals of the many gods and goddesses in the Egyptian system. The cat goddess Bastet was one of the Egyptian gods who were honored by sacrificing animals—cats—which were then mummified. The system was far crueler than it might sound like, because worshippers could choose live cats bred for the purpose, which were then killed and later mummified. Cats were common animals in Egypt, as pets, as potential sacrifices and mostly as a way to control rats and mice. Current theories say that the domestic cat we know was created by the Egyptians from different breeds of wilder cats. The period during which cats were often mummified ran almost a thousand years, roughly 600 BCE to 250 CE. The numbers of mummified cats must have been in the tens of millions. In the years around 1880 to 1900 tons and tons of them were exported to Britain, where they were used to fertilize English fields.