What was Georgia a military barrier between?

The colony of Georgia, founded in 1732, was as a buffer state (or a border), between Spanish Florida and the southern part of the British colonies (South Carolina). General James Oglethorpehoped that Georgia that would defend the southern part of the colonies from Spanish Florida, as he imagined a province populated by "sturdy farmers" that could guard the border; because of this, the colony's charter prohibited slavery.