Dream interpretation is known to have gone on for millennia. It is mentioned in some Sumerian texts, for example, meaning that it goes back to 3000 BCE, at least. In ancient Egypt, it is known that certain priestly functions were associated with dream interpretation. Ancient Greeks also built some of their divine culture based on the way they 'incubated' dreams. In later times, working out what dreams may mean has been the focus of interest among several Islamic scholars as well as the subject of some 16th-century texts in China. In Europe, Sir Thomas Browne, a 17th-century physician, was among the first thinkers to publish scholarly works about dreams.