Aasim bin Alee, the Shaykh of al-Bukhaaree, (d. 221H)
We have reported from Aasim bin Alee bin Aasim al-Waasitee, [that] he said:

I debated a Jahmee and it became clear from his speech that he does not believe there is a Lord above the heaven.
I say: Aasim was a haafidh (memorizer), from the vessels of knowledge, truthful. He carried (knowledge) from Shu'bah, Ibn Abee Dhi'b and a portion of others. Al-Khateeb mentions in his biography that [the caliph] al-Mu'tasim appointed a person to estimate the gathering of this Aasim in the open space of the grand mosque of ar-Rasaafah, and he used to sit on the roof of the open space, and the people used to sit in the open space and what was after it. So one occasion the gathering was very large until he had to say, "Al-Layth bin Sa'd narrated to us ..." fourteen times as the people could not hear due to their large number. And the scribe Haaroon (writing from Aasim's dictation) would gather (from) date-palm trees, writing on them. So they estimated the gathering and it was 120,000. And Yahyaa bin Ma'een said, "Aasim bin Alee is the leader of the Muslims".
Source: "Mukhtasar al-Uluww" of adh-Dhahabee, (p. 179)