Before Hohenheim was Edward and Alphonse's father, before he met their mother, before he had become a monster, a philosopher stone, he was a person.

A slave, but a person nonetheless.

Then he had met that wretched thing, the thing that had ruined him trying to achieve God.

Homunculus.

In its quest, it had turned both of them immortal.

Afterwards, Hohenheim had been broken. He stayed in the same place for years, never leaving for about a millennia.

After a while, he realized that he could not go on like this, and had headed to the first place he could think of.

No, not Xing.

Not Amestris either.

The country he went to was called Lucifenia.