Complex sentence: This is because before Kalam came under the rule of Swat it was a region tributary to Chitral the Kalamis paid a tribute of mountain ponies to the Mehtar of Chitral every year.
Split into simpler sentences: This is because before Kalam came under the rule of Swat, it was a region tributary to Chitral. The Kalamis paid a tribute of mountain ponies to the Mehtar of Chitral every year.