Complex sentence: In old times Kazi-Kumukh was a major trading center--here on Thursdays arrived merchants not only from Derbent, Sheki and Shemakha, but also from Bukhara, Istanbul and Hindustan.
Split into simpler sentences: In old times Kazi-Kumukh was a major trading center. Here on Thursdays arrived merchants not only from Derbent, Sheki and Shemakha, but also from Bukhara, Istanbul and Hindustan.