How to respond to Christians' claim that Alexander the Great died at the age of 33, while it is affirmed in the Quran that he died in old age?

A Muslim is not permitted to read the misconceptions of Christians or engage in religious dialogues with them, except for those deeply rooted in knowledge. This is because hearts are weak and misconceptions are captivating; they may settle in the heart, making their removal difficult. As for what you mentioned about Alexander the Great, it is a misconception that indicates the ignorance of Christians, and its answer is from several angles:

1. There is no mention in the Holy Quran of the age of Dhu al-Qarnayn or the era in which he lived. 2. Dhu al-Qarnayn mentioned in the Quran is not Alexander the Great, the Greek Macedonian who built Alexandria. The latter died at 33 years of age and lived 323 years before Christ, whereas the Quranic Dhu al-Qarnayn was in the time of Abraham (peace be upon him). 3. The difference between the righteous Dhu al-Qarnayn and the disbelieving Alexander the Great is well-known among Muslim scholars. Ibn Kathir clarified that the former was a righteous believer, while the latter was a polytheist, and there is a significant time difference between them. 4. There is no sufficient information in the Christian holy book about the second Alexander, let alone the first. 5. The existence of differences between the Quran and their book is not strange because their books are distorted, lack authentic chains of narration, and contain many contradictions. Therefore, they cannot be made a judge over the preserved Quran.