Phrenology is a pseudomedicine primarily focused on measurements of the human skull, based on the concept that the brain is the organ of the mind, and that certain brain areas have localized, specific functions or modules. Although both of those ideas have a basis in reality, phrenology beyond empirical knowledge in a way that departed from science. Developed by German physician Franz Joseph Gall in 1796, the discipline was very popular in the 19th century, especially from about 1810 until 1840. The principal British centre for phrenology was Edinburgh, where the Edinburgh Phrenological Society was established in 1820.