Imam Mahmood bin Ahmad bin Musa is most often referred to as Badr al-Deen al-Ayni. He is one of the greatest scholars of the Hanafi tradition, with numerous authoritative works. His commentary on al-Hidayah (al-Binayah) is one of the most relied upon books in the Hanafi Madhab.
As well as Fiqh he has made a significant contribution in the field of Hadith. He is best known for his commentary of Sahih al-Bukhari (Umdatu al-Qari). However, he has numerous other important Hadith works.
Imam al-Ayni passed away in the year 855 Hijri.