People often confuse these 2 great Shafi’i ‘ulama from Egypt. Who were they? Some short biographical info.
1.) ‘Ali b. Abu Bakr b. Sulayman al-Haythami (d. 807 AH / 1404 CE)
In Arabic: الهيثمي
He was a muhaddith and student of the great imam Zayn ud-Din al-‘Iraqi.
He was THE expert on zawa’id literature in hadith and compiled many works in this field. His most famous work is a great encyclopedia of hadith: Majma’ az-Zawa’id wa manba’ al-Fawa’id.
2.) Ibn Hajar al-Haytami al-Makki [not to be confused in his turn with Ibn Hajar al-‘Asqalani] (d. 973/974 AH)
In Arabic: الهيتمي
He was a muhaddith but also a great faqih, a student of imam Zakariya al-Ansari and Shihab ad-Din al-Ramli. He was ONE the 3 main authorities in the maddhab.
Famous for his Fatawa al-Haytamiyyah, sharh on the 40 hadith of an-Nawawi and the sharh of the Minhaj by an-Nawawi
As we can see they lived in different centuries. People often mistake them and in transcribing their names (t and th) they makes mistakes as well, just like Ibn al-Jawzi and Ibn Qayyim al-Jawziyyah. They had their own specialities in hadith and fiqh.
May Allah have mercy on them.