I believe you should have a firm grasp on European History either before or during your time spent reading and studying Political Philosophy. I will provide one example:
I. The Ancient Greeks:
Socrates, Plato and Aristotle were real people living in a real life city called Athens 2300-2500 years ago. During their combined lifetimes-(148 years to be exact), Athens, was the only Democracy in the Greek world and it was constantly facing threats from its arch Rivals Sparta, Persia, Macedon, (as well as from within). Greek Democracy during the lifetimes of Socrates, Plato and Aristotle was not consecutive and at times, was interrupted by nondemocratic regimes and rulers. It would be difficult to understand The Trial of Socrates, The Republic or The Laws from an ahistorical context; that is to say, studying these works and not knowing about the reality that Socrates and Plato lived through and WHY they were so contemptuous and distrustful of Democracy and Citizen Power.
It should also be noted that Plato did travel to Sicily in his younger years to establish his Republic. Much to his dismay, Plato was imprisoned by the Tyrant of Syracuse and barely escaped execution. Neither the Tyrant of Syracuse, nor the Athenian Boule, were enthusiastic supporters of Plato's Political Philosophy.
In Aristotle's case, he was a native of Macedonia, though spent many years in Athens, thereby living under two very different political systems....Macedonian Monarchy and Athenian Democracy. Aristotle's lectures reveal to us that he was no supporter of Monarchy, though was mildly supportive of Democracy-(more specifically, a Citizen's based Democracy, a.k.a. "Politea"). Aristotle was a personal friend of King Philip of Macedon and his Father, was the Top Physician to the Royal Court of Macedon. Aristotle also tutored Alexander The Great; and like Socrates 80 years earlier, Aristotle was under investigation by the Athenian Council for heresy towards the end of his life. Aristotle's life experiences, in a way, may have greatly contributed to his understanding of how Power should be exercised and that constraints on Power, were absolutely indispensable in maintaining a civilized society.
Now if you have little or no understanding of Ancient Greek History during the lifetimes of Socrates, Plato and Aristotle, then their ideas are just abstractions and have no real value or applicability. However, a combined study of History and Political Philosophy, can provide you with a better, deeper and more nuanced understanding of the reality these men lived through and how, as well as WHY, they wanted to transform it.