Complex sentence: This initiation was crucial because through Panagiotis, the Filiki Eteria jointed the Istanbul's merchants who gave financial assistance to Athanasios, while their influence and skills facilitated the expansion of its network.
Split into simpler sentences: This initiation was crucial because, through Panagiotis, the Filiki Eteria jointed the Istanbul's merchants. They gave financial assistance to Athanasios, while their influence and skills facilitated the expansion of its network.