These travels were not limited to Punjab only rather they were long tours that covered various religious shrines in India and abroad. These tours are popularly known as Char Udasis of Guru Nanak Sahib. Kurukshetra, Haridwar, Joshi Math, Ratha Sahib, Nanak Matta, Ayodhya, Prayag, Varanasi, Gaya, Patna, Guwahati, Puri, Cuttack, zameshwaram, Ceylon, Bidar, Baroach, Somnath, Dwarka, Janagarh, Ujjain, Ajmer, Mathura, Pakpattan, Talwandi, Lahore, Sultanpur, Bilaspur, Rawalsar, Jawalaji, Spiti Vally, Tibet, Ladakh, Kargil, Amarnath, Srinagar and Baramula were all covered by Nanak during these tours. He even went to several Muslim shrines like Mecca, Medina, Beghdad via Multan and Peshawar.His tour aimed at general awakening of the masses in order to bring about a realization of God. Nanak even appointed certain able and dedicated followers as preachers of Sikhism. This was observed as sowing the seeds of Sikhism all over India and abroad in a planned manner.
Guru Nanak Sahib JI was arrested and released later in the year 1520, after he challenged the barbarity of Mughal Emperor Babar who invaded India at that time. Thence, the saint settled down at Kartarpur city (now in Pakistan in 1522 and stayed there for the rest of his life till1539. Having sensed his end, this divine being installed Bhai Lehna ji (Guru Angad Sahib) as his successor in 1539. Nanak established Sewa, Kirtan, Satsang and faith in God as the fundamental concepts of Sikhism. He preached the theory of a formless or Nirankar creator to his followers who is believed to be an ever lasting creator or Karta Purakh. Also acting as a social reformer, Nanak Sahib also worked hard for the upliftment of women, downtrodden and the poor. The citadel of Hindu caste system also suffered a great blow form Him. Having written 947 hyms of Japuji Sahib, Asa Di Var, Bara Mah, Sidh Gosht and Dakhani, Nanak is definitely regarded as a born poet. An amalgamation of a saint, poet, social reformer and a born leader, Nanak was considered not the image of God, but God Himself by Guru Arjan Sahib Ji.