Guru Nanak (1469-1539) was a prominent figure during the late 15th to early 16th centuries, coinciding with the fall of the Lodi dynasty and Babur's establishment of the Mughal Empire in 1526. His teachings laid the foundation for Sikhism, emphasizing monotheism, equality, and social justice, which were progressive ideas emerging against the socio-religious backdrop of that period. In contrast, Dadu Dayal and Tyagaraja were active in later periods, thus making Guru Nanak the only relevant Bhakti saint during this significant transition in Indian history.