have been found in an area near Changanassery, thus supporting the hypothesis. Archaeological studies have identified many Mesolithic, Neolithic and Megalithic sites in the eastern highlands of Kerala mainly centred around the eastern mountain ranges of Western Ghats. Rock engravings in the Edakkal Caves, in Wayanad date back to the Neolithic era around 6000 BCE. These findings have been classified into Laterite rock-cut caves (Chenkallara), Hood stones (Kudakkallu), Hat stones (Toppikallu), Dolmenoid cists (Kalvrtham), Urn burials (Nannangadi) and Menhirs (Pulachikallu). The studies point to the indigenous development of the ancient Kerala society and its culture beginning from the Paleolithic age, and its continuity through Mesolithic, Neolithic and Megalithic ages. However, foreign cultural contacts have assisted this cultural formation. The studies suggest possible relationship with Indus Valley civilization during the late Bronze Age and early Iron Age. Archaeological findings include dolmens of the Neolithic era in the Marayur area. They are locally known as "muniyara", derived from muni (hermit or sage) and ara (dolmen). Rock engravings in the Edakkal Caves in Wayanad are thought to date from the early to late Neolithic eras around 5000 BCE. Historian M. R. Raghava Varier of the Kerala state archaeology department identified a sign of "a man with jar cup" in the engravings, which is the most distinct motif of the Indus valley civilisation. Classical period Early ruling dynasties Kerala's dominant rulers of the early historic period were the Cheras, a Tamil dynasty with its headquarters located in Vanchi. The location of Vanchi is generally considered near the ancient port city of Muziris in Kerala. However, Karur in modern Tamil Nadu is also pointed out as the location of the capital city of Cheras. Another view suggests the reign of Cheras from multiple capitals. The Chera kingdom consisted of a major part of modern Kerala and Kongunadu which comprises western districts of modern Tamil Nadu like Coimbatore and Salem. The region around Coimbatore was ruled by the Cheras during Sangam period between c. 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. Old Tamil works such as Patiṟṟuppattu, Patiṉeṇmēlkaṇakku and Silappatikaram are important sources that describe the Cheras from the early centuries CE. Together with the Cholas and Pandyas the Cheras formed the Tamil triumvirate of the mūvēntar (Three Crowned Kings). The Cheras ruled the western