It is to be remarked that all kinds of numbers are uncertain in ancient manuscripts, and have been subject to much greater corruptions than any other part of the text, and that for a very obvious reason. Any alteration in other places commonly affects the sense or grammar, and is more readily perceived by the reader and transcriber. Few enumerations of inhabitants have been made of any tract of country by any ancient author of good authority so as to afford us a large enough view for comparison. It is probable that there was formerly a good foundation for the number of citizens assigned to any free city, because they entered for a share of the government, and there were exact registers kept of them. But as the number of slaves is seldom mentioned, this leaves us in as great uncertainty as ever with regard to the populousness even of single cities. The first page of Thucydides is, in my opinion, the commencement of real history. All preceding narrations are so intermixed with fable that philosophers ought to abandon them, in a great measure, to the embellishment of poets and orators.​[70] With regard to remote times, the numbers of people assigned are often ridiculous, and lose all credit and authority. The free citizens of Sybaris, able to bear arms and actually drawn out in battle, were 300,000. They encountered at Siagra with 100,000 citizens of Crotona, another Greek city contiguous to them, and were defeated. This is Diodorus Siculus’s account, and is very seriously insisted on by that historian. Strabo also mentions the same number of Sybarites. Diodorus Siculus, enumerating the inhabitants of Agrigentum, when it was destroyed by the Carthaginians, says that they amounted to 20,000 citizens, 200,000 strangers, besides slaves, who, in so opulent a city as he represents it, would probably be at least as numerous. We must remark that the women and the children are not included, and that therefore, upon the whole, the city must have contained near two millions of inhabitants.​[71] And what was the reason of so immense an increase! They were very industrious in cultivating the neighbouring fields, not exceeding a small English county; and they traded with their wine and oil to Africa, which, at that time, had none of these commodities. Ptolemy, says Theocritus, commanded 33,339 cities. I suppose the singularity of the number was the reason of assigning it. Diodorus Siculus assigns three millions of inhabitants to Egypt, a very small number; but then he makes the number of their cities amount to 18,000—an evident contradiction. He says the people were formerly seven millions. Thus remote times are always most envied and admired.