Complex sentence: This is a collective memory of the Catalan occupation many centuries ago, from South Italy; then in the whole country, there is Gogoli, that indeed means "the Mongol" and is a collective memory of the Golden horde.
Split into simpler sentences: This is a collective memory of the Catalan occupation many centuries ago, from South Italy. Then in the whole country there is Gogoli, that indeed means "the Mongol" and is a collective memory of the Golden horde.