Hari Singh Nalwa killed at Jamrud

Who: Sardar Hari Singh Nalwa, governor of Peshawar and the Khalsa army's foremost general on the north-west frontier; the Jamrud garrison; and an Afghan force under Wazir Akbar Khan. Dost Muhammad Khan, the ruler at Kabul, afterwards sent an apology saying his sons had acted without his authority (Wikipedia).

What: In 1836 Nalwa built a fort at Jamrud, at the mouth of the Khyber Pass, to block invasion from the north-west. On 30 April 1837 an Afghan army under Akbar Khan attacked it. In Wikipedia's account Akbar Khan arrived, found no Sikh force in the field and began pulling down the fort's defences. Nalwa led a charge that threw the Afghans into disarray, but they rallied and pushed the Sikhs back inside the fort. The Encyclopaedia of Sikhism says Nalwa was badly wounded, kept giving orders, was carried to the fort and died there that evening. His last instruction was to keep his death secret until Ranjit Singh's relief column arrived. Some eyewitness accounts add that his body was shown outside the fort so the Afghans would think him alive. The garrison held until reinforcements came from Lahore, and the Afghans withdrew towards Jalalabad.

Where: Jamrud, a village at the eastern approach to the Khyber Pass, now in Pakistan.

Why it mattered: The Khalsa army lost the commander who had governed Kashmir from 1820 and Peshawar from 1834. Historians divide on the result: some call it a Sikh success because the Afghans failed to take the fort or Peshawar, others an Afghan one because Nalwa died, and J. A. Norris calls it largely inconclusive. Afterwards Dost Muhammad proposed that Peshawar be entrusted to him; the Darbar refused, reorganised the Peshawar government under General Paolo Avitabile and kept a strong garrison at the new fort of Shabqadar. Peshawar remained under Lahore until the war of 1848 and 1849.