Freud's view of phobias can be discussed in three main phases. Freud sees the traumatic events and the emotions associated with these phenomena as the cause of phobias in the first phase, which lasted until 1905. In the second phase from 1905 to 1923, the main axis was based on the abandonment of the seduction hypothesis and the development of the libido theory. In the third phase, following the introduction of the structural model in The Ego and the Id in 1923, Freud's final views on phobias, where the emphasis fell on the defensive functions of the ego, are shaped. Freud reviews the theory of anxiety in The Inhibitions, Symptoms and Anxiety in 1926, in line with his views on the mental economy, the pleasure principle, and the structural model. Freud's anxiety theory contains significant changes in symptom formation; instead of repression causes anxiety, signal anxiety, an ego response to a situation of perceived danger, causes the defending. This view was applied to all psychonevrotic symptoms including phobias.