The Old Republic

The Senate of the Old Republic started as a forum to resolve disputes between Systems. Over time it grew and evolved, eventually becoming the ruling body of the Republic.
Sometimes when the systems involved in the disputes disagreed with the Senate's rulings, war could result between the systems. Unlike individual systems, the Senate never had any sort of armed force to enforce it's decisions, but it was not completely powerless.

The Jedi

The origins of the Jedi are unknown. The time that they first appeared in the Old Rebuplic has been debated for almost as long as they have they have existed.
Their "religion", like the Jedi themselves, varied from Jedi to Jedi. Each individual had their own approach to their religion. It has no fixed base, no fixed set of rules, no holy book.
Some Jedi would safeguard a single system, others would roam from system to system, never visiting the same system twice, still others would have a regular route, visiting the same systems over and over. There seemed to be as many approaches to being a Jedi as there were Jedi.
What they all had in common was their affinity with the Force and their love of Truth and Justice.

The Jedi and the Old Republic

After the arrival of the Jedi in the Old Republic, the Senate found that any decisions it made that lead to conflict, had Jedi intervene in them. But the Jedi did not always fight to enforce the Senate's decisions. They had their own reasons for joining the conflict, the Jedi always fought on the side of Justice. The Jedi's intervention could decide the outcome of a conflict, often overcoming incredible odds to protect Peace and Justice.
The representatives in the Senate soon learnt that they could not control the Jedi, and that unjust or corrupt decisions would often be opposed by the Jedi. This lead to an age of prosperity and peace in the Republic.

Next: The Coming of the Dark Times