This Datacron unlocks the codex entry - Galactic History 12: The Bith of the Republic
This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:
For centuries, safe and reliable travel through hyperspace had been the biggest obstacle to galactic exploration. Finally, Corellian scientists managed to perfect hyperdrive technology on par with that of the ancient Rakata, allowing travel between the Core Worlds in mere days. Joined by trade and renewed communication channels, the Core Worlds signed an accord and united as the first Galactic Republic.
The newborn Republic began exploration of hyperspace routes in earnest, supported by daring Duros scouts and eventually established the Perlemian Trade Route. This route connected Coruscant to many worlds, including Ossus, where the Jedi Order's enclave had been established centuries before. The Jedi welcomed Republic scouts with curiosity and interest.
The head of the enclave, Master Haune Tiar, returned with the scouts to the allied Core Worlds. Impressed by what he saw, Master Tiar also foresaw the young Republic would need protectors. After conferring for several weeks, the Jedi pledged themselves as the Republic's guardians of peace and justice. The foundations for the modern Republic were laid.
Coordinates: X -656, Y 44
This is by far the easiest Datacron to find on Ord Mantell since it is visible from a frequently traveled path. The Datacron is on Savrip Island which is in kinda southwestern Ord Mantell. This Datacron is just northeast of the Presence +2 one, you literally have to pass right by it in order to get to the Presence Datacron. For that reason I recommend grabbing both of these back-to-back before you head over to the Red Matrix Shard. Anyway, onto how to reach this Datacron. From the path that leads right by it (Screenshot 1) head across the river to Savrip Island.
Once on the island you will want to circle around back to the side that faces the ocean. From here you'll want to find a small little dirt slope that leads you onto the plateau opposite of where the Datacron is (Screenshot 1 & 2). Once here it's easy, make your way across the little rock bridge (Screenshot 3) and up onto the plateau. Once up here the Datacron is all yours!