Complex sentence: By the time Evliya Çelebi had arrived almost all the towns he visited were affected by the Cossack raids in fact the only place Evliya Çelebi considered safe from the Cossacks was the Ottoman fortress at Arabat.
Split into simpler sentences: By the time Evliya Çelebi had arrived almost all the towns he visited were affected by the Cossack raids. In fact, the only place Evliya Çelebi considered safe from the Cossacks was the Ottoman fortress at Arabat.