ATAR SIṄGH, SANT (1867-1927), of Gurdwārā Reṛū Sāhib at Rāmpur, in Ludhiāṇā district in the Punjab, was born in March 1867 at the village of Lopoṅ, now in Farīdkoṭ district. He was the son of Lāl Siṅgh, the village headman. Atar Siṅgh was married in 1885 to Bishan Kaur of Ṭoḍarpur, a village near Samrālā. A son, Indar Siṅgh, was born to them in 1887. On 8 June 1887, Atar Siṅgh enlisted in the 36th Sikh Battalion (present 2nd Battalion of the Sikh Regiment). While in the army, he received the vows of the Khālsā. He was promoted sergeant on 16 June 1896. Once, while his battalion was in the Peshāwar region, he along with several of his comrades went to see Sant Karam Siṅgh of Hotī-Mardān, who was then widely known for his piety. Atar Siṅgh, a devout Sikh, instantly fell under the saint's spell, and determined to lead a life of sevā (service) and simran (meditation). Once, while on leave from his regiment, he visited Rāmpur where he found the old historical shrine, Reṛū Sāhib, commemorating Gurū Gobind Siṅgh's brief halt under a reṛū tree (Mimosa leucophloea) during his journey from Māchhīvāṛā towards the Mālvā country in December 1705, in a dilapidated state and determined to have it rebuilt. During his next leave, in 1901, he with the help of the local saṅgat reconstructed Mañjī Sāhib, the inner sanctum. He spent his leave periods expanding the building and, after his retirement on 18 October 1907, he settled permanently at Rāmpur. He developed Gurū kā Laṅgar, and initiated monthly congregations on full-moon days. He also opened a school where young boys, especially the poor and the blind, were imparted instruction in scripture-reading and kīrtan or hymn-singing with a view to training them as preachers of Sikhism.

        Sant Atar Siṅgh died at Gurdwārā Reṛū Sāhib on 21 January 1927. He was succeeded by Sant Bhagvān Siṅgh who kept the Reṛū Sāhib legend alive. Sant Bhagvān Siṅgh continued to manage the Gurdwārā until his death in 1975.