Initially, several generations after the Taba-Tabaeen, auditory gatherings of Zikr began to spread throughout the Muslim community. These gatherings, to some degree, originated with the efforts of Hazrat Junaid Baghdadi (ra). Later, they also incorporated the recitation of early Naat.
Over time, Sufi Elders recognized the need for dedicated Tasawwuf centers, providing sanctuary for many Majzoobeen who were misunderstood by society at large. While serving as a refuge for Ehl-e-Tasawwuf, these centers also served as venues for Zikr gatherings. Gradually, they came to be known as Zawiyahs (referred to as Khanqah in the Indian Subcontinent). The gatherings held in these places were called Mehfil-e-Sama.
Only later on, in the times of Hazrat Khwaja Ghareeb Nawaz (ra), did the idea of Qawwali took root. But now, after so many centuries, when the term Mehfil-e-Sama is used, it usually means a gathering to hear Qawwali.