Imam Husain(a.s) is Syed ush Shuhdah(Chief of Martyrs)

Objection : It was Hazrat Hamzah (ra) who was 'Syed ush Shuhdah' but later on Shias attributed this title to Imam Husayn

We would like to reply that till his period Hazrat Hamzah was exalted martyr among other martyrs that is because he was 'Syed ush Shuhdah' till that time but Imam Husayn touched the highest stage of martyrdom which entitled him to be called 'Syed ush Shuhdah'. And its not only Shias but a vast majority of Ahle Sunnah ulema also call him 'Syed ush Shuhdah'. For example Maulana Ahktar Shah of Merath (India) has called him as 'Syed ush Shuhdah' (see Tasdeeq e Shahadat, page 94), Maulana Shah Muhammad Suleman Phulwari in his 'Risala Shahadat Husayn o Risala Gham e Husayn' has written Imam Husayn as 'Syed ush Shuhdah', Maulana Muhammad Mubeen in his esteemed book 'Wasilat ul Nijaat ' (published in Lucknow) has written Imam Husayn as 'Syed ush Shuhdah' at many places. Moreover Imam of Ahle Sunnah and renowned anti Shia scholar Maulana Shah Abdul Aziz Dehalwi writes in his book:

"Syed ush shuhdah Imam Husayn (ra) attained martyrdom by the hands of enemies"
 

Reference :Tauhfa Athna Ashari, page 28 published by Fakhar al Matab`e 1268