The region was a prominent spice exporter from 3000 BCE to 3rd century. The Chera Dynasty was the first powerful kingdom based in Kerala, though it frequently struggled against attacks from the neighbouring Cholas and Pandyas. During the Chera period Kerala remained an international spice trading center. Later, in the 15th century, the lucrative spice trade attracted Portuguese traders to Kerala, and eventually paved the way for the European colonisation of the whole of India. After independence, Travancore and Cochin joined the Republic of India and Travancore-Cochin was given the status of a state. Later, the state was formed in 1956 by merging the Malabar district, Travancore-Cochin (excluding four southern taluks), and the taluk of Kasargod, South Kanara.
Kerala is the state with the lowest positive population growth rate in India (3.44%) and has a density of 819 people per km2. The state has the highest Human Development Index (HDI) (0.790) in the country according to the Human Development Report 2011.[3] It also has the highest literacy rate (93.91%), the highest life expectancy (74 years) and the highest sex ratio (as defined by number of women per 1000 men: 1,083 women per 1000 men) among all Indian states. Kerala has the lowest homicide rate among Indian states, for 2011 it was 1.1 per 100,000.[5] A survey in 2005 by Transparency International ranked it as the least corrupt