Prima

"We are Primus. We are Prima. We are Prime Nova. We are Sentinel Prime. We are Optimus Prime."

Prima?

Prima was the first Matrix bearer, as dictated by the Creation Matrix itself. He is possibly the first Transformer.

It is uncertain what relationship he has, if any, to Primon, another early Matrix bearer who may have also have been the first Transformer.

Footnotes

From Teletraan I: The Transformers Wiki, a Wikia wiki.