The term, which now means 'chaste woman,' or 'virtuous woman' derived from the origional name of Gauri or Dakshayani, Goddess of marital longevity and contentment, whom Hindi women pray to in pursuit of long lives for their husbands. According to Hindu mythology, she was the wife of Dakhsha, and was so overcome at his death that she immolated herself on his funeral pyre.
The act, in many instances, had culturally been considered as a required act for a pious woman, and was not considered as suicide in her case, but an act of righteousness, purging the couple of their shared sins to guarantee their salvation and eternal union beyond death.
The Greeks believed the practiced emerged as a means of discouraging wives from poisoning their husbands.
Speculation suggests the possibility that the ritual carried the sense of culminating the marriage, as in a related act husbands and wives dressed in their wedding clothes and re-enact the ritual before parting to die.
Hero-stones commemorating the occurrences claim wives committed Sati out of love so great for their husbands that they wanted to be together after death, but history indicates otherwise. In Rajasthan, the woman seems to die to protect their honor from invading enemies after their husbands died in battle. (Kamat)
One source credits the 'halo of honour' associated with Sati, with its perpetuation--mainly among the Rajput marital caste who committed collective suicide after a battle in which male members had died at an enemy's hand. The act, more formally known as Jouhar in this case, was even committed before husbands actually died at times of certain defeat. Indians keep the memory of these women alive by songs glorifying their act. (Vivaaha)
Women committing the act came to be believed to go directly to heaven, redeeming any forefathers that rot in hell. (Kamat)
Another argument from some Hindu scholars is that the practice was never related to any doctrine, but emerged as a way for Hindu women to escape the stigma associated with rape during the Islamic invasion of India, to protect their honor in the midst of numerous acts of mass rape of easily captured city women. With the choice between glorification and honor or the lonely shunning and potential abuse of widowhood, it seems clear why women may have preferred the former option.
One source notes that sati was nearly absent among other castes and aboriginal tribes, and more prevalent among the priestly and martial castes of Brahmins and Kshatriyas, in which a bride was looked upon as a burden draining the family's income while contributing nothing to it. Thus, it seems inevitable that her presence would be even more indicative of deadweight among the in-laws after the husband's death. They considered the touch, voice, and appearance of a widow as unholy, impure, and abhorrable, thus making her presence intolerable. Remarriage was nearly impossible due to the sanctity of a bride's virginity. Furthermore, a woman was literally considered as part of her husband, almost completely lacking individuality--without him, she became no one. (Vivaaha)
Most instances of sati occurred voluntarily, on the day of the husband's death--and thus without much time to reconsider, yet possibly as a result of cultural, or at least, community expectations since the widow had little to expect out of life following the husband's death, particularly if she has yet to bear children.
Apparently, there were some instances of measures being taken to prevent the widow from committing the act, on specific occasions.
One version of sati is merely symbolic, and lacks the actual death of the widow, in which the woman lies next to her dead husband in enactments of the marriage and funeral ceremonies, but leaves unharmed.
There were also instances, however, of widows being physically forced to commit sati, even beyond the cultural pressures that existed. Now, in modern India, the practice is illegal to attempt, promote, or watch. It was banned in 1829 by the British government, then needed to be banned again in 1956 after a resurgence--and again after another revival in 1981. (Indianchild)
The most recent account took place in 2002, when a 65-year old woman burned to death on her husband's funeral pyre. According to reports, her two adult sons made no attempt to stop her, and 4000 onlooking villagers pelted police officers with stone to keep them from interfering with the ceremony. After the event, local witnesses declared that they wanted to worship the woman as their new goddess. Prior to this occurrence of sati, the most recent had been in Rajasthan in 1987, when 18-year old Roop Kanwar burned to death. (BBC)
In 1996, the Indian Court freed the relatives who assisted Roop Kanwar (...), upholding the suicide as a social tradition. (Kamat's Potpourri- tradition thru the centuries)
However, the case attracted widespread media attention that led to legislation that called for the death penalty of anyone (abetting) sati... Nevertheless, mentions of the act still tends to evoke sentiments of deep respect among villagers. (BBC)
As remarriage for widows remain uncommon, they still feel shunned or forced into poverty and a life alone by in-laws who blame them for their husbands' death and instill a fear of potential abuse (e.g. sexual, or starvation) if they stick around.
More recently, many widowed women have run away voluntarily, by the thousands, often to Vrindavan--so many and so often, in fact, that the city has come to be known in India as the "city of widows," where they know they will at least be provided with daily rations of a cup of rice and 7 cents. The city's ashrams are controversial among women's rights groups, who clam that they have turned these women's misery into an enterprise, as they raise tens of thousands per year but choose to leave the women there in poverty. (CNN)