Freud believed that personalities started developing from birth in a series of psychosexual stages. As a child progresses in maturity, he or she will also progress through the stages. If a child cannot get past one of the stages their development may be hindered. The first psychosexual stage is the oral stage which takes place in the very first year after birth. Next is the anal stage which takes place during years 2-3 and then, what Freud believes to be the most important stage, the phallic stage, 3-roughly 6 years of age. This is the stage in which Freud believes that the child wishes to get rid of the parent from the same sex to as to have the remaining parent to the child's self. This is called the Oedipus complex and once this is out of the child's system, that is when their personality can truly develop individually.
Freud's theories were received surprisingly well, a lot of scholars thought that his timing in the stages were done well and that there was some merit to his theory. Not everyone felt this way though and even today there are still some people who are unsure as to the credibility of his theory and preferred to go by a modified version of Freud's theory and then of course there are those who broke off from him altogether and went there own way when it came to personalities.