Dost Mohammad Khan

At the beginning of his rule, the Afghans lost their former stronghold of Peshawar Valley in March 1823 to the Sikh Khalsa Army of Ranjit Singh at the Battle of Nowshera. The Afghan forces in the battle were led by Azim Khan, half-brother of Dost Mohammad Khan. By the end of his reign, he had reunited the principalities of Kandahar and Herat with Kabul. Dost had ruled for a lengthy 36 years, a span exceeded only by Zahir Shah more than a century later.
A brilliant strategist, and ruthless fighter from a young age, Dost Mohammad is regarded as one of the greatest rulers in the history of Afghanistan, his myriad of campaigns had successfully forged the cities of Kabul, Kandahar, and Herat into one state, which all his predecessors, with the exception of Ahmad Shah Durrani, had failed to do. Provided by Wikipedia