Urza was the first to ascend to divine status. Honoured by those who respect makers and thinkers in the Old Faith, he is also revered by the Divine King devotees.
Nymarga was the second mortal to ascend to godhood. He is mostly reviled as a demigod of avarice and undeath, and yet some still whisper his name...
Mishra was the third mortal to ascend to divinity. His was the hardest road, one fraught with suffering, though he did leave an indelible mark upon Creation.