ATAR SINGH, SANT (1867-1927), of Gurdwara Reru Sahib at Rampur, in Ludhiana district in the Punjab, was born in March 1867 at the village of Lopon, now in Faridkot district. He was the son of Lal Singh, the village headman. Atar Singh was married in 1885 to Bishan Kaur ofTodarpur, a village near Samrala. A son, Indar Singh, was born to them in 1887. 

On 8 June 1887, Atar Singh enlisted in the 36th Sikh Battalion (present 2nd Battalion of the Sikh Regiment). While in the army, he received the vows of the Khalsa. He was promoted sergeant on 16 June 1896.Once, while his battalion was in the Peshawar region, he along with several of his comrades went to see Sant Karam Singh of HotiMardan, who was then widely known for his piety.

Atar Singh, a devout Sikh, instantly fell under the saint`s spell, and determined to lead a life of seva (service) and simran (meditation). Once, while on leave from his regiment, he visited Rampur where he found the old his torical shrine, Reru Sahib, commemorating Guru Gobind Singh`s brief halt under a reru tree (Mimosa leucophloea) during his journey from Machnivara towards the Malva 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 sangat reconstructed Manji Sahib, the inner sanctum. He spent his leave periods expanding the building and, after his retirement on 18 October 1907, he settled permanently at Rampur.

He developed Guru ka Langar, 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 kirtan or hymnsinging with a view to training them as preachers of Sikhism. Sant Atar Singh died at Gurdwara Reru Sahib on 21 January 1927. He was succeeded by Sant Bhagvan Singh who kept the Reru Sahib legend alive. Sant Bhagvan Singh continued to manage the Gurdwara until his death in 1975.

References :

1. Azad, Sohan Singh, Jivan Gatha Sant Atar Singh. Ludhiana, 1971
2. Mehar Singh, Giani, Amar Katha.