Brahmin (also known as Brahman) caste is the top most caste in the caste system in India.
According to the tenets of the caste sytem, Brahmins originated from the head of the Hindu God 'Brahma', that's why the top position.
Various indologists consider the Brahmins to have been Aryan migrants from the region around Iran, eastern Eurasia or central Asia.
They are considered to have arrived in India around 3500 years ago, alongwith others and drove the native Indian population towards the south of the sub-continent.
In the caste system, the Brahmins are a priestly caste and as per the caste Bible 'Manusmriti', all religious duties, teaching and learning was exclusively reserved for them.
However, although the Brahmins are at the top of the caste system, it is concurred that this was not always the case. Rather, it was the Kshatriya (ruler, warrior caste) that was at the top.
With passage of time, however, while the Kshatriyas were busy conquering local territitores and populations, the Brahmins edged them out of the top spot by introducing religious laws that gave them pre-eminence.
With the gradual waning of the caste system, legally replaced by the democratic order in India, Brahmins have coinsiderably lost their power and say over the population, whereas in the heyday of caste system, even insulting a Brahmin led to severe punsihment including cutting off of the tongue.
All the same, in a caste ridden society, Brahmins continue to hold a lot of the top positons in democratic India, including offices in politics and business. At the bottom of the ladder are dalits.
For instance, between 1950-2000, over 47% of the chief justices in India came from
the Brahmin caste and over 50% of the associate justices were Brahmins.
Similarly many of the top politicians in the country such as Pranab Mukherjee, Murli Manohar Joshi, A B Vajpayee, J Jayalalitha, Buddhadeb Bhattacharya, Sehila Dixit and Somnath Chatterjee, among others, are Brahmins.
Brahmin Priests at A Temple
With the rise of low caste political parties, hoever, there has been a reducing number of Brahmins who enter parliament.
For instance the statistics of Brhamin menbers of parliament in the Hindi belt reads thus:
The current parliament has just 50 Brahmin MPs nationwide, which is about 9.17% per cent of the total strength.
Brahmins also continue to control most, if not all, the affluent and wealthy Hindu institutions and temples. Many of the temple trusts generate annual revenues that equal the GDP of many nations, which gives an idea of the kind of clout they wield.
With the extremely gradual decline of caste and their hegemony over it, Brahmins have made their presence also felt in non-priestly occupations.
Within the Brhamin caste, you also have sub-castes and the caste is broadly divided into two types: the Pancha-Gauda Brahmins from North India and Pancha-Dravida Brahmins from South India.
Brahmins are expected to be endogamus as per the religious laws set out for them.
NOTE: You can get very detailed and extensive information about Brahmins and their role in the caste system in the eBook 'Truth About Dalits'.