The first five centuries after the fall of Alamut in 1256 comprise the most obscure phase in Nizari Ismaili history. For at least two centuries, the Nizaris did not have direct access to the Imams, who were living discreetly in various parts of Persia. In order to avoid persecution, the Nizaris sought refuge under the mantle of Sufism. The Nizaris had, since the time of Hasan Sabbah, adopted Persian in preference to Arabic as their religious language. This commonality of language as well as the esoteric nature of the Ismaili tariqa facilitated the Ismaili-Sufi relationship.
As a result, the Persian-speaking Ismailis have regarded some of the greatest mystic poets of Persia as their co-religionists and selections of their poetry have been preserved in the private Ismaili libraries of Badakhshan, now divided between Afghanistan and Tajikistan. Some of these poets include Farid al-Din Attar, Jalal al-Din Rumi, and Qasim al-Anwar. The Nizari Ismailis of Persia, Afghanistan, and Central Asia have continued to use verses by the mystical poets of Persia in their various religious rituals and ceremonies; the origins of such traditions may be traced to the Ismaili-Sufi encounters of the early post-Alamut centuries.