543

The year 543 (DXLIII) predates the launch of the Transformers brand by 1441 years.

For further information, see: Transformers timeline

Fiction

The Transformers cartoon

During a battle in 1985, several Autobots and Decepticons (and Spike Witwicky) stumble upon a cave which contains energies that cause them to time travel to this year. After interacting with the locals a bit, they make their way back to the cave (guarded by a dragon) and return to their proper time. A Decepticon Raider in King Arthur's Court