Asbāb al-nuzūl (أسباب النزول), meaning occasions or circumstances of revelation, refers to the historical context in which Quranic verses were revealed. Though of some use in reconstructing the Qur'an's historicity, asbāb is by nature an exegetical rather than a historiographical genre, and as such usually associates the verses it explicates with general situations rather than specific events.
The material in this application was taken from a book written by Alī ibn Ahmad al-Wāhidī.