The roots of the Enneagram types come from Oscar Ichazo's ego types. The ego types identified how a person was fixated in ego and the remedy for finding freedom from that.
Type 4 Fixation and Trap
Fixation: Melancholy comes from a dissatisfaction with what is and a longing for what once was or could've been.
Trap: Authenticity comes from finding a sense of self and significance that expresses your unique gifts and individuality.
The fixation of melancholy points to the mental preoccupation of the type 4 ego. The trap of authenticity keeps an individual stuck in the fixation.
Type 4 Holy Idea
Holy Idea: Holy Originality involves accepting the common and ordinary in life instead of disdaining it in favor of the unique and special.
The fixation of melancholy and trap of authenticity keep an individual stuck in the type 4 fixation. The way out of that fixation is through holy originality.
Type 4 Passion
Passion: Envy is a one-sided comparison between the positives of others and the negatives of oneself. "What's lacking in me that I don't have what they have?"
The passion of envy is the emotional energy that serves the fixation of melancholy and trap of authenticity.
Type 4 Virtue
Virtue: Equanimity appears when you also see the positives you have to offer instead of just the negatives when comparing yourself to others.
The virtue of equanimity is what appears when the passion of envy subsides.