According to Sebast Mathon, the Yan Jung nation immigrated into New Eden through the EVE Gate and settled in the Deltole system, especially on Deltole V and VI, which seem to have been much more inhabitable back then.
The Yan Jung were, judging from the remains of Yan Jung technology found in the archaeological record, masters of advanced gravitronic technology and force field theories.
Yan Jung archaeological sites can be found in the Algintal Constellation within Gallente Federation space.
"The Yan Jung nation immigrated into our world through the EVE Gate eons ago. From where, we do not know, though the fragments of texts we've managed to translate talk about a mysterious middle kingdom. They settled here in Deltole, though we suspect they also colonized other systems, even in far off places. But what we've uncovered so far is here in the Deltole system, especially on Deltole V and VI, which seem to have been much more inhabitable back then."
– Sebast Mathon, Professor of Archaeology, University of Caille