Julius Caesar epilepsy cause

I've been watching Rome, the series on HBO, interspersed with the Olympics. It's a good mix, an ancient Greek tradition brought into the modern world and the history of Rome presented to the modern world. I'm never clear on how much of what you see in these types of shows are based on facts so I was interested to find this piece on Julius Caesar's epilepsy and what may have caused it.

The proper medical or surgical treatment would then be instituted. A reconstruction of the clinical history of Julius Caesar (100-44 B.C.) has been attempted from available information from literature. Although a definite conclusion obviously cannot be made, a differential diagnosis provided with a tentative hypothesis is presented. The patient had late onset of seizures in the last two years of his life, headaches, personality changes.

Golly, seizures, possible brain tumor, assassination, by his friends no less; the poor man had it rough.