If by "I have looked everywhere and can't find it," you mean
"I have used ancestry.com, geni.com and also even googled his name," you actually have looked practically nowhere but in junk trees.
Start by reading Gibbons' Decline and Fall of the Roman Empire and absorb it all (the Cliffs Notes version simply will not do). Study Greek and Latin so you can understand his quotations. Study all writings by Herodotus. Study all documents retrieved by the Crusaders from Toledo.
Next go to England and check about 300 archaeological and historical repositories for fragmentary records of the Roman Legion and their commanders who occupied England.
Next do the same in France and Germany and Romania and Bulgaria.
After about 10 years you might begin to get an overall picture.
Next go to Italy. Work 5 years to get permission to explore the archives in the Vatican, since you won't yet have any formal academic credentials as a scholar in this field. Work another 2 years to figure out what archives there may be in public-access and private libraries elsewhere in Italy. Work a few years to get permission to utilize private archives. Work around 10 years exploring material in the archives you've obtained permission to get a look at.
Oh, and learn how to speak French and German fluently, and learn how to read and translate old Latin (allow around 8 years for these pesky details). Internet translation programs will not do the job for you.
So by around the year 2055 you can say you have looked almost everywhere.