Complex sentence: During his reign the Kazakhs were able to muster an army of 50,000 men and to repeatedly defeat the forces of Muhammad Shaybani along the Syr Darya river.
Split into simpler sentences: During his reign, the Kazakhs were able to raise an army of 50,000. Under Buryndyq Khan, the Kazakhs fought several more times with the forces of Muhammad Shaybani along the Syr Darya river.