The Land of Keralaputra was one of the four independent kingdoms in southern India during Ashoka's time, the others being Chola, Pandya, and Satiyaputra.[46] Scholars hold that Keralaputra is an alternate name of the Cheras, the first dominant dynasty who ruled Kerala, and had its capital at Karur.[47][48] These territories once shared a common language and culture, within an area known as Tamilakam.[49] The region around Coimbatore was ruled by the Cheras during Sangam period between 1st and the 4th centuries CE and it served as the eastern entrance to the Palakkad Gap, the principal trade route between the Malabar Coast and Tamil Nadu.[50] Along with the Ay kingdom in the south and the Ezhimala kingdom in the north, the Cheras formed the ruling kingdoms of Kerala in the early years of the Common Era (CE).[51] It is noted in Sangam literature that the Chera king Uthiyan Cheralathan ruled most of modern Kerala from his capital in Kuttanad,[52][53] and controlled the port of Muziris, but its southern tip was in the kingdom of Pandyas,[54] which had a trading port sometimes identified in ancient Western sources as Nelcynda (or Neacyndi) in Quilon.[55] Tyndis was a major center of trade, next only to Muziris, between the Cheras and the Roman Empire.[56] The lesser known Ays and Mushikas kingdoms lay to the south and north of the Chera regions, respectively.[57][58] Pliny the Elder (1st century CE) states that the port of Tyndis was located at the northwestern border of Keprobotos (Chera dynasty).[59] The North Malabar region, which lies north of the port at Tyndis, was ruled by the kingdom of Ezhimala during Sangam period.[60] The port at Tyndis which was on the northern side of Muziris, as mentioned in Greco-Roman writings, was somewhere around Kozhikode.[60] Its exact location is a matter of dispute.[60] The suggested locations are Ponnani, Tanur, Beypore-Chaliyam-Kadalundi-Vallikkunnu, and Koyilandy.[60]