For the next 'movie', maybe the Transformers were on earth during the first century in Rome. Caligula came to power with the help of of the Decepticons & Megatron. But then Prime & Bumblebee stop them. While wearing Togas! Then they all Fight Fight Fight for 90 minutes and the script writes itself! There's also a long scene where Prime fights Megatron in the arena at the coliseum. "Transformers: Of Gods & Emperors". I assume, since the the Transformers take their summer vacation on earth & have been here so many times in our history, that is entirely plausible in the little mind of Michael Bay.