The SDF-1 was actually Created by Zor a Robotech Master.
Zor had Stolen the Flower of Life from the Invid, created Protoculture, and then in turn used protoculture to power his robotechknowlodgy.
The Robotech Masters had then enslaved the Zentradi and used them as warriors to conquer the galaxy. - The Zendtri previously having been a quiet gentle race of miners.
Eventualy Zor came to realise the evil that he had done, when the Rototech master destroyed the Invid's homeworld, the only place known to grow the Flower of life, and so he built the SDF-1.
He then 'stole' his own creation away from the Robotch masters, and sent it to earth, where the macros saga then takes place.
A correction for the above node: Zor Prime was a Clone of Zor, the 1st of about 20 or so, created by the Invid in an attempt to work out what Zor had done with the SDF-1, and how protoculture worked. He was brought to earth during the Invid's invasion of Earth, and fell in love with Dana Hayes the Daughter of Rick and lisa Hayes, who had left to go face the Robotech masters, unkowning about The Invid. They (Rick and Lisa) went on to form a group called The Sentinels.