Today, I told my students that while Socrates was not the first philosopher, he is the one who really set what would come to be called Western Philosophy in motion. I don't know exactly how accurate that view is since there were a number of odd mystery cults circulated in the Mediterranean, Pythagoras and his crew for instance. Nevertheless, there is something about the drama of the trial and death of Socrates that seemed to energize the philosophical project, such as it was at the time.
Even if created in retrospect, the narrative of a person dying for asking questions sends a powerful signal that there is something important about what he was doing. Remember that it's not quite right to say that Socrates died for his ideas. The early dialogues offer little in the way of a positive project, and what is there is usually attributed to Plato working out the early stages of his project. In the end, Socrates is executed because asking questions is dangerous. It undermines the structure of authority, erodes certainty in traditional values, and disrupts social routines.
Nevertheless, it's also the ability to question that grounds our capacity for self-understanding and rational thought. The death of Socrates marks a cultural awakening to sentience mirrored in the roots of other great world traditions, named and unnamed. All of us inherit those traditions, whether we recognize the lineage or not.