After his father's death, Shri Guru Hargobind Ji added the martial element to Sikhism which was until then a religion mainly focused on Spirituality.
Hence Shri Guru Hargobind Ji started recruiting an army which he called "Risaldari", after training his men in cavalry and Sikh Martial Arts.
So the 6th Guru at one point managed to command 700 cavalry and with this might his Risaldari fought several small scale battles in 1620s and 1630s against Shahjahan's forces and some other warlords in Poadh and Majha.
[citation needed] The Afghans led numerous campaigns to re-capture Lahore but ultimately had to return to Pashtun territories due to internal strife.
His coronation on 12 April 1801 marked the beginning of the Sikh Empire, which went on to conquer the whole Punjab, Kangra, parts of Kashmir and briefly, the city of Peshawar.