In 1848, Babi leaders gathered at the hamlet of Badasht to debate how far the new revelation broke from the Islamic law it had emerged within. At the height of the gathering, Tahirih appeared before the assembled men without the veil that custom required, an act every account treats as a deliberate announcement that the old law's claim on the movement had ended. The reaction was immediate: some of those present were horrified, one is said to have cut his own throat rather than witness it, while others, understanding the point being made, accepted it as confirmation that a new dispensation had begun. Babi historiography reads the moment as the movement's formal, public break with Islamic legal authority, staged by the one person whose religious learning gave the gesture its force.
She continued teaching and was repeatedly placed under house arrest as Babi and government tension escalated through the following years. In August 1852 a small group of Babis, acting without any sanction from the movement's leadership, attempted to assassinate Nasir al-Din Shah; the reprisal that followed swept up Babis with no connection to the plot, Tahirih among them. She was executed in a garden in Tehran in 1852, and Baha'i accounts hold that her last words declared that her killers could stop her but not the freedom of women that her life had argued for. Baha'i writings, including those of Abdu'l-Baha, name her among the movement's foundational figures, and her poetry survives and continues to be read as Babi and Baha'i literature in its own right.