While anti-Iranian sentiment is present particularly among Sunni Arabs it´s highly interesting that all six authors of the so called canonical “Sahih Hadith” books were Iranians:
http://saeedtalpur.wordpress.com/2013/12/11/six-persian-iranian-imams-sunni-hadith-collectors/

“According to the Cambridge History of Iran: After this period commences the age of the authors of the six canonical collections of Sunni hadith, all of whom were Persian. The authors of the six collections are as follows:

1. Muhammad b. Isma’il al-Bukhari, the author of the Sahih Bukhari, which he composed over a period of sixteen years. Traditional sources quote Bukhari as saying that he did not record any hadith before performing ablution and praying. Bukhari died near Samarqand in 256/869-70.
2. Muslim b. Hajjaj al-Naishapuri, who died in Nishapur in 261/ 874-5 and whose Sahih Muslim is second in authenticity only to that of Bukhari.
3. Abu Dawood Sulaiman b. Ash’ath al-Sijistani, a Persian but of Arab descent, who died in 275/888-9.
4. Muhammad b. ‘Isa al-Tirmidhi, the author of the well-known as Sunan al-Tirmidhi, who was a student of Bukhari and died in 279/892-3.
5. Abu ‘Abd al-Rahman al-Nasa’i, who was from Khurasan and died in 303/915-16.
6. Ibn Majah al-Qazwini, who died in 273/886-7.”

Source: http://en.wikipedia.org/wiki/Kutub_al-Sittah

In addition two of the most relevant early islamic historians, Tabari and Baladhuri were Iranians:
http://en.wikipedia.org/wiki/Muhammad_ibn_Jarir_al-Tabari
http://en.wikipedia.org/wiki/Baladhuri