The spread of Islam in the Sub-continent is the story of untiring efforts of numerous saints and Sufis who dedicated their lives to the cause of service to humanity. By the time the Muslim Empire was established at Delhi, Sufi fraternities had come into being and the Sufi influence was far more powerful than it was in earlier days under the Arabs in Sindh. The two great fraternities that established themselves very early in Muslim India were the Suhrawardiyah and the Chishtiyah. The Suhrawardiyah order was founded by Sheikh Ab-al-Najib Suhrawardi (1097 - 1162) and was introduced into Muslim India by Sheikh Baha-ud-din Zakariya (1182 - 1268) of Multan. With Multan as its center the Silsilah became dominant in the areas that now constitute Pakistan. Hadrat Khawaja Muin-ud-din introduced the Chishtiyah Silsilah in the Sub-continent. He settled in Ajmer. Because he established the first Sufi Silsilah in the Indian sub-continent, he is often referred to as Hind-al-Wali. Khawaja Muin-ud-din Ajmeri's chief disciple, Khawaja Qutb-ud-din Bakhtiyar Kaki, who lived at Delhi, was held in high esteem by Iltutmush. Baba Farid who was the disciple of Khawaja Qutb-ud-din Bakhtiyar Kaki, decided to settle in Punjab. The Chishtiyah order remained the most popular order during the Sultanate period.