Answer
Kindly be more specific. Hereunder is a general explanation to your query:
The Muhadditheen that lived in the era of the four Imaams, before them and after them hailed from different lands and were from different schools of thought. They were people who devoted their lives for the preservation of the legacy of Hadith of Rasulullah (Sallallaahu Alayhi Wasallam).
May Allah Almighty reward them duly for their efforts and sacrifices in this path. Refer to the Madrasah website for some incidents concerning their sacrifice and extreme thirst for this esteemed legacy.
and Allah Ta’ala Knows Best
Moulana Muhammad ibn Moulana Haroon Abassommar
FACULTY OF SPECIALTY IN HADITH
CHECKED AND APPROVED: Mufti Ebrahim Desai