The term 'Six French Kings' refers to the six kings of the Capetian dynasty, which ruled France from 987 to 1328. The first king of this dynasty was Hugh Capet, and the last was Charles IV. The most famous of these kings was Philip II, also known as Philip Augustus, who reigned from 1180 to 1223. He is often credited with establishing the foundations of the French state and is remembered for his military successes against England and other European powers.