ISLAMABAD, Pakistan — She has been isolated on death row for eight years after an accusation with little evidence that she had spoken against the Prophet Muhammad. A prominent governor who spoke out in her defense was killed by his own bodyguard, and mobs have rallied against the suggestion that leniency might be in order.

But for the first time since her arrest in 2009, Asia Bibi, the Christian Pakistani woman whose blasphemy conviction the following year rallied international condemnation of a law that has inspired violence again and again, is free.

Pakistan’s Supreme Court on Wednesday fully acquitted her and ordered her “released forthwith,” in an exceptionally rare ruling against a blasphemy verdict. The ruling, by a three-member bench of the court, was announced by Chief Justice Mian Saqib Nisar.

“This is a landmark verdict,” said Omar Waraich, the deputy South Asia director at Amnesty International. “Despite her protest of innocence, and despite the lack of evidence against her, this case was used to rouse angry mobs, justify the assassinations of two senior officials, and intimidate the Pakistani state into capitulation. Justice has finally prevailed.”