This area of study began for Broca with the dispute between the proponents of cerebral localization – whose views derived from the phrenology of Franz Joseph Gall – and their opponents led by Pierre Flourens. Phrenologists believed that the human mind has a set of various mental faculties, each one represented in a different area of the brain. With specific areas representing personality characteristics like one's aggressiveness or spirituality, but also memory and linguistic abilities. Their opponents claimed that, by careful ablation (specific way of removing material) of various brain regions, Flourens had disproved Gall's hypotheses. However, Gall's former student, Jean-Baptiste Bouillaud, kept the localization of function hypothesis alive (especially with regards to a "language center"), although he rejected much of the remaining phrenological thinking. In 1848, Bouillaud relied on his work with brain damaged patients to challenge other professionals to disprove him by finding a case of frontal lobe damage unaccompanied by a disorder of speech. His son-in-law, Ernest Aubertin (1825–1893), began seeking out cases to either support or disprove the theory, and he found several in support of it.