The following little story is related in al-Sharazuri’s entry on the famous exegete and historian al-Tabari. As you could gather from the story, al-Tabari’s two most renowned works were his massive tafsir and his equally massive history (tarikh) of the world, with a particular emphasis upon the parts he knew best, of course (the image above is taken from a later, partially illumined copy of his history). As the humorous story below demonstrates, he could have made both far longer. That, at least, was the perception of later scholars (like al-Sharazuri, who lived hundreds of years after al-Tabari) who had come to see al-Tabari as one of the crowning jewels of Muslim scholarship- though, this story might also insinuate, such an ability might be more than ordinary scholars could handle…
Al-Qadi Abu ‘Umar ‘Ubid Allah ibn Ahmad al-Samsar and Abu al-Qasm ibn ‘Aqil al-Waraq said that once Abu Ja’afar al-Tabari said to his disciples: ‘Are you in the mood for commentary on the Qur’an (atanshatun li-tafsir al-Qur’an)?’ They replied: ‘How long is it going to be?’ He said: ‘Thirty thousand pages,’ to which they replied: ‘This would use up entire lifetimes before it could be completed!’ So he condensed it to approximately three thousand pages. Then he said to them: ‘How do you feel about a history of the world from the time of Adam up to our own time?’ They replied: ‘How long is it going to be?’ So he said what he had said about the commentary, and the replied in the same way, to which he said: ‘Good Lord! Ambition is dead.’ So he condensed it in the same fashion as he had condensed the commentary.
Al-Sharazuri, Ṭabaqāt al-Fuqahāʼ al-Shāfiʻīyah