The earliest written record mentioning Kerala is contained in the Sanskrit epic known as the Aitareya Aranyaka. Later, such figures as Katyayana (circa 4th century BC) and Patanjali (circa 2nd century BC) exhibited in their writings a casual familiarity with Kerala’s geography. Megasthanes, the Greek Ambassador to the court of Emperor Chandra Gupta Maurya (4th Century BC) mentions in his work Indica on many South Indian States, including Automela (probably Muziris), and a Pandian trade centre. Ancient Roman Natural philosopher Pliny the Elder mentions in his Naturalis Historia (N.H. 6.26) a Muziris (probably modern-day Kodungallur or Pattanam as India’s first port of Importance. Later, the unknown author of the Periplus of the Erythraean Sea notes that “both Muziris and Nelkunda (modern Neendakara) are now busy places”.
There is evidence of the emergence of prehistoric pottery and granite burial monuments in the form of megalithic tombs in the 10th century BC; they resemble their counterparts in Western Europe and other parts of Asia. These are thought to be produced by speakers of a proto-Tamil language. Kerala and Tamil Nadu once shared a common language, ethnicity and culture; this common area was known as Tamilakam.
The ancient Cheras, whose mother tongue and court language was ancient Tamil, ruled Kerala from their capital at Vanchi. They were constantly at war with the neighbouring Chola and Pandya kingdoms. A Keralite identity, distinct from the Tamils and associated with the second Chera empire, became linguistically separate under the Kulasekhara dynasty (c. 800–1102). By the beginning of the 14th century, Ravi Varma Kulasekhara of Venad established a short-lived supremacy over southern India. After his death, Kerala became a conglomeration of warring chieftaincies, among which the most important were Calicut in the north and Venad in the south.
The Chera kings’ dependence on trade meant that merchants from West Asia and Southern Europe established coastal posts and settlements in Kerala.:192–195, 303–307 The west Asian-semitic Jewish, Christian, and Muslim immigrants established Nasrani Mappila, Juda Mappila and Muslim Mappila communities.The Jews first arrived in Kerala in 573 BC.The works of scholars and Eastern Christian writings state that Thomas the Apostle visited Muziris in Kerala in 52 AD to proselytize amongst Kerala’s Jewish settlements.
However, the first verifiable migration of Jewish-Nasrani families to Kerala is of the arrival of Knanai Thoma in 345 AD.Muslim merchants (Malik ibn Dinar) settled in Kerala by the 8th century AD and introduced Islam. After Vasco Da Gama’s arrival in 1498, the Portuguese gained control of the lucrative pepper trade by subduing Keralite communities and commerce.
Southern India in the latter half of the 18th century. Tipu Sultan ceded Malabar District to the British in 1792, and South Kanara, which included present-day Kasargod District, in 1799. The British concluded treaties of subsidiary alliance with the rulers of Cochin (1791) and Travancore (1795)*, and they became princely states of British India, maintaining local autonomy in return for a fixed annual tribute to the British. Malabar and South Kanara districts were part of British India’s Madras Presidency.
*Rulers of Kingdom of Travancore
Rama Varma 1663-1672
Aditya Varma 1672-1677
Umayamma Rani‡ 1677-1684
Ravi Varma 1684-1718
Aditya Varma 1718-1719
Unni Kerala Varma 1719-1724
Rajah Rama Varma 1724-1729
Marthanda Varma 1729-1758
Dharma Raja 1758-1798
Balarama Varma 1798-1810
Gowri Lakshmi Bayi‡ 1810-1815
Gowri Parvati Bayi‡ 1815-1829
Swathi Thirunal 1829-1846
Uthram Thirunal 1846-1860
Ayilyam Thirunal 1860-1880
Visakham Thirunal 1880-1885
Moolam Thirunal 1885-1924
Sethu Lakshmi Bayi‡ 1924-1931
Chithira Thirunal 1931-1949
Organised expressions of discontent with British rule were relatively infrequent in Kerala. Uprisings of note include the rebellion by Pazhassi Raja, Velu Thampi Dalawa, and the Punnapra-Vayalar revolt of 1946. Mass protests were mainly directed at established social evils such as untouchability. The non-violent and largely peaceful Vaikom Satyagraha of 1924 was instrumental in securing entry to the public roads adjacent to the Vaikom temple for people belonging to backward castes. In 1936, Sree Chithira Thirunal Balaramavarma The respected Maharaja, ruler of Travancore issued the Temple Entry Proclamation, declaring the temples of his kingdom open to all Hindu worshippers, irrespective of caste.
After India’s independence in 1947, the princely states of Travancore and Kochi were merged to form the province (after 1950 a state) of Travancore-Cochin on July 1, 1949. Madras Presidency became India’s Madras State.
The state of Kerala was created on November 1, 1956 when Malabar District was merged with Tranvancore-Cochin state and Kasargod taluk of South Kanara District to form the State of Kerala, based on the recommendations of the State Reorganisation Commission set up by the Government of India. Elections for the new Kerala Legislative Assembly were held in 1957; this resulted in the formation of a communist-led government headed by E.M.S. Namboodiripad. Many Indians consider this the first democratically elected communist government in the world; however, both San Marino (in 1948) and Guyana (in 1953) had elected communists to power years earlier. Radical reforms introduced by the Namboodiripad government in favour of farmers and labourers helped change, to a great extent, the iniquitous social order that had prevailed in Kerala for centuries.
Ref: Wikipedia, History of Kerala by KP Padmanabha Menon, Kerala Hisoty by Sreedhara Menon