Kerala was little and no evidence of his influence is noticed in the literature or other things in his lifetime in Kerala. Even though Sankara was against all caste systems, in later years his name was used extensively by the Brahmins of Kerala for establishing caste system in Kerala. The Kingdom of Kozhikode Historical records regarding the origin of the Samoothiri of Kozhikode is obscure. However, its generally agreed that the Samoothiri were originally the Nair chieftains of Eralnadu region of the Later Chera Kingdom and were known as the Eradis. Eralnadu (Eranad) province was situated in the northern parts of present-day Malappuram district and was landlocked by the Valluvanad and Polanadu in the west. Legends such as Keralolpathi tell the establishment of a local ruling family at Nediyiruppu, near present-day Kondotty by two young brothers belonging to the Eradi clan. The brothers, Manikkan and Vikraman were the most trusted generals in the army of the Cheras. M.G.S. Narayanan, an Indian historian, in his book, Calicut: The City of Truth states that the Eradi was a favourite of the last Later Chera king and granted him, as a mark of favor, a small tract of land on the sea-coast in addition to his hereditary possessions (Eralnadu province). Eradis subsequently moved their capital to the coastal marshy lands and established the kingdom of Kozhikode They later assumed the title of Samudrāthiri ("one who has the sea for his border") and continued to rule from Kozhikode. Samoothiri allied with Muslim Arab and Chinese merchants and used most of the wealth from Kozhikode to develop his military power. They became the most powerful king in the Malayalam speaking regions during the Middle Ages. In the 14th century, Kozhikode conquered large parts of central Kerala following the seize of Tirunavaya from Valluvanad, which was under the control of the king of Perumbadappu Swaroopam. He was forced to shift his capital (c. CE 1405) further south from Kodungallur to Kochi. In the 15th century, Cochin was reduced in to a vassal state of Kozhikode. The ruler of Kolathunadu (Kannur) had also came under the influence of Zamorin by the end of the 15th century. At the peak of their reign, the Zamorins of Kozhikode ruled over a region from Kollam (Quilon) in the south to Panthalayini Kollam (Koyilandy) in the north. Ibn Battuta (1342–1347), who visited the city of Kozhikode six times, gives the earliest