Why might have been the system of philosophy developed by the Greek Philosopher important foe effective leadership?

In The Republic, Plato outlines his view on leadership through a discussion on civic and political life in the Polis, the Grecian city state. Apart from focusing on the meaning of justice, he also develops a framework on the nature of leadership in an ideal state.

Be a "lover of wisdom," a cardinal virtue

Plato was dissatisfied with rulers who lacked knowledge and moral strength to act according to the common good - in other words, rulers motivated by self-interest were not strong leaders. Plato proposes instead that states should be governed by philosophers and be a lover of wisdom, which is the meaning of the Greek word, philosophia.