She was one of the disciples (known in Arabic as Sahaba or companions) of Islamic prophet Muhammad, and a warrior who participated in the battles of Uhud, Hunain, and Yamamah.
[1] When 74 leaders, warriors, and statesmen of Medina descended on al-Aqabah to swear an oath of allegiance to Islam following the teaching of the new religion by Mus`ab ibn `Umair in the city, Nusaybah and Umm Munee Asma bint ʿAmr bin 'Adi were the only two women to personally pledge directly to the Islamic prophet Muhammad.
The latter's husband, Ghazyah bin ʿAmr, informed Muhammad that the women also wanted to give them their bayah in person, and he agreed.
This bayah or pledge was in fact handing over power to Muhammad over the city, by its key figures.
In the book Explaining the Harakat of the hard names of narrators, their ancestry, and kunyas (Arabic: توضيح المشتبه في ضبط أسماء الرواة وأنسابهم وألقابهم وكناهم) by the classic scholar of hadith Ibn Nasir Al-Din Al-Dimashqi (ابن ناصر الدين) [4] he mentions the name of Umm 'Ammarah as spelt نَسِيبة بنت كعب (Nusaybah bint Kaab) [5] with the name Nusaybah attributed instead to Nusaybah Bint al-Harith (also Umm ʾAtiyyah)