Ibn Hajr and Ibn Kathir on the Inventor of the Mawlid
regards the celebration of the birthday of the Messenger (sallalahu 'alayhi wa sallam), the scholars have clearly stated that
the person who first introduced this innovation (bid’ah) was Muzaffar ad-Din ibn Zain al-Din, the ruler of Irbil. "He
was a prodigal monarch. He commanded the scholars of his time to follow the conduct based on their own derivation and independent
thinking (ijtihaad), and that they should not follow any school of law of any master except their own. A group of scholars
and a body of the servants inclined towards him. He used to celebrate the birthday of the first monarch to introduce this
practice among the Muslims"
used to spend one hundred thousand (dirhams) on the celebration of the birthday of the Messenger (sallalahu 'alayhi wa sallam)
every year. 
assistant and helper in this innovation was Abdul Khattab Umar b. Dihya. "He was employed in the Maghrib, then travelled to
Syria, then to Iraq, and then went to Irbil in 604 A.H. and found its monarch Muzaffar al-Din b. Zain al-Din who took keen
interest in celebrating the birthday of the Messenger (sallalahu 'alayhi wa sallam). He composed a book for him al-Tanwir
fi Maulid al-Siraj al-Munir and recited it to him. He rewarded him with one thousand dinars."
Kathir has reported on the authority of al-Sabt about Ibn Dihya: "Ibn Unain used to defame the Muslims and disparage them.
He would make additions in his report and exaggerate. So the people gave up narrating traditions from him and falsified him.
Kamil was favouring him. When his conduct was disclosed to him, he withdrew Dar-al-Hadith from him and disgraced him."
give below the resume of Ibn Hajar al-Asqalani's comments on him: "He was a liar, lied frequently, and a fabricator. He often
slandered the scholars and the jurists of the past, used evil tongue, self-conceited, lacked insight in religious matters,
and looked down upon religion. This has been reported from al-Hafiz Diya. He further says: Ali b. al-Hussein Abul Ali al-
Isbahan narrated to me - it is enough to mention his name as an authority - when Ibn Dihya came to us in Isbahan, he stayed
with my father in the hospice. He honoured and respected him very much. One day he came to my father with a carpet. He kissed
it and placed it before him saying, "I offered such and such thousand rak'ahs of prayer on this carpet, and recited the whole
Qur'an in the Ka'ba." He said: My father took it, kissed it, placed it on his head, and accepted it from him with a great
pleasure. At the end of the day an inhabitant of Isbafian came and began to talk to us. During his conversation he said by
chance: The faqih of Maghrib who is staying with you has purchased a beautiful carpet today for such and such a price. Thereupon
my father ordered to bring the carpet. Seeing it the man said, "Yes by Allah, this is the same." My father kept silent, and
the eyes of Ibn Dihya fell down. 
Ahmad b. Muhammad el-Misry, el-Qawl el-Mu'tamad fi 'amal al-Mawlid
Al-Dhahabi, Duwal al-Islam, Vol.11 p.102
Ibn Kathir, al-Bidaya wa al-Nihaya, Vol.I3 pp.144-146
Ibn Hajar el-Asqalani, Lisan al-Mizan, VoL 4 p. 295