Sikhism achieved a series of military victories and created a Sikh Empire in 1799. The Sikh empire had its capital in Lahore, spread over almost comprising what is now northwestern Indian subcontinent. The Sikh Empire entered into a treaty with the colonial British powers, with each side recognizing Sutlej River as the line of control and agreeing not to invade the other side. Ranjit Singh's most lasting legacy was the restoration and expansion of the Harmandir Sahib, most revered Gurudwara of the Sikhs, with marble and gold, from which the popular name of the "Golden Temple" is derived. After the death
Sikhism charge of upkeep of the historical gurdwaras of Punjab, adopted Nanakshahi calendar. The new calendar is highly controversial among Sikhs and is not universally accepted. Sikh festivals include the following: Khalsa Sikhs have also supported and helped develop major pilgrimage traditions to sacred sites such as Harmandir Sahib, Anandpur Sahib, Fatehgarh Sahib, Patna Sahib, Hazur Nanded Sahib, Hemkund Sahib and others. Sikh pilgrims and Sikhs of other sects customarily consider these as holy and a part of their "Tirath". The Hola Mohalla around the festival of Holi, for example, is a ceremonial and customary gathering every year in Anandpur Sahib