Who is Dhul-Qarnayn mentioned in the Qur’an?

Dhul-Qarnayn, mentioned in the Quran, was a righteous king among the kings of the Earth. He called people to Islam, fought its enemies, and spread justice. He, along with Solomon, ruled over the Earth from its east to its west. Among those who disbelieved were Nebuchadnezzar and Nimrod. Dhul-Qarnayn was most likely not a prophet, and the hadith "I do not know if Tubba' was a prophet or not, and I do not know if Dhul-Qarnayn was a prophet or not" is not authentic. He is not Alexander the Great, for Dhul-Qarnayn was a Muslim and lived in a very ancient time, whereas Alexander was a disbeliever and lived more than two thousand years after him.