Option 1 states that Sufism was the mystical interpretation that developed within Islam. This statement is correct. Sufism is indeed a mystical and spiritual dimension of Islam that focuses on the inner, esoteric aspects of the faith. Sufism seeks to attain a direct connection with the divine through practices such as meditation, chanting, and asceticism.

Option 2 states that Sufi philosophy highlighted the atmosphere of religious tolerance by speaking about universal love in the quest for the Almighty. This statement is also correct. Sufism emphasizes love and compassion as central elements of the spiritual path. Sufis believe in the unity of all creation and promote religious tolerance and understanding.

Option 3 states that the Sufis developed a very complex philosophy and initiated complicated practices unintelligible to the masses. This statement is incorrect. While Sufism does have its own unique practices and concepts, it does not necessarily mean they are unintelligible to the masses. Sufi teachings often emphasize simplicity and accessibility, aiming to bring people closer to the divine regardless of their level of knowledge or understanding.

Therefore, the correct answer is option 1, which states that statements 1 and 2 are correct.