he was one of the first to come up with the idea that collecting a small amount of simple taxes instead of many and complex taxes will increase the tax revenues of the country.
sociologist and historian, whom a western scientist called "the machiavelli of the islamic world". against this statement, master cemil meriç said "it's not a compliment, it's slander".
there is a section (serlevha) in his muqaddime. the sultan's dealing with trade is harmful to the subjects, it disrupts the tax system.
(see mukaddime) by the way, muqaddime is not the name of ibni khaldun's book, it is the preface, and it is not the original of the book, but became famous for its preface. because in arabic, preface means preface.
he has a very famous book called mukaddime that is still read. with this book, he is seen as the founder of philosophy of history and even sociology. in one part of the book, he says that the skin color of hot climate people is black because of the sun and white because of the cold in the north, which is considered quite radical since it was the beginning of the 15th century. he lived in algeria, died in 1434. he stayed as a guest in the palace of his abbasi caliph in egypt for a while, and wrote another book at the request of the caliph, but it was already forgotten.