Complex sentence: Subsequently, they progressed along the valleys of Alpine rivers towards the Karawanken range and towards the settlement of Poetovio (modern Ptuj), where the decline of the local diocese is recorded before 577.
Split into simpler sentences: Subsequently, they progressed along the valleys of Alpine rivers towards the Karawanken range and towards the settlement of Poetovio (modern Ptuj). In Poetovio, the decline of the local diocese is recorded before 577.