Throughout their works historians explicitly or implicit boasted of their rigorous work by calling attention to or implying that they travelled to acquire their information..
• Herodotus (484-428 BC): “I also heard other things at Memphis… I visited Thebes and Heliopolis… I wished to know… took ship for Tyre in Phoenicia, where I had learned by inquiry… did not tally with the belief of the Greeks” [The Histories 2.3, 44]; “no one that conversed with me, Egyptian, Libyan, or Greek, professed to know…” [The Histories 2.19-24] “Here are presented the results of the enquiry carried out by Herodotus of Halicarnassus. The purpose is to prevent the traces of human events from being erased by time, and to preserve the fame of the important and remarkable achievements produced by both Greeks and non-Greeks; among the matters covered is, in particular, the cause of the hostilities between Greeks and non-Greeks.” [The Histories, introductory paragraph]; “I know this, because I was told at Dodona” [The Histories 2.52]
• Thucydides (460-400 BC): ““For I well remember… often repeated saying that it was to last thrice nine years.I lived through the whole of it, …associating with both sides, with the Peloponnesians quite as much as with the Athenians, because of my exile, I was thus enabled to watch quietly the course of events.” [History of the Peloponnesian War 5.26]
• Polybius: “I speak with confidence on these points, because I have questioned persons actually engaged on the facts; and have inspected the country, and gone over the Alpine pass myself, in order to inform myself of the truth and see with my own eyes.” [The Histories 3.48]; “I am aware that it has been stated at forty stades; but this is false, as I know from personal inspection and not from mere report,—and in our day it has been still farther contracted” [The Histories 10.11.4] [Note: See Polybius's comments on travelling to obtain witness testimony/approval here]
• Appian of Alexandria (95-165 AD): “[m]y history has often led me from Carthage to Spain, from Spain to Sicily or to Macedonia, or to join some embassy to foreign countries, or some alliance formed with them; thence back to Carthage or Sicily, like a wanderer, and again elsewhere, while the work was still unfinished. At last I have brought the parts together, ... I have made this research also in respect to each of the other provinces, desiring to learn the Romans' relations to each, in order to understand…” [Roman History Praef. 1.12]
The historians enjoyed cataloguing a range of details one would most naturally only be able to acquire by visiting the different locals.
• Thucydides's work brims with such details.1
• Pausanias’s work brims with such details.2
• Polybius’s work brims with such details.3
Historians often enough straightforwardly express in their writings that traveling to see the land and interrogate witnesses is of utmost importance to the very project of history.
• Flavius Josephus: “[s]ome of their contemporaries daring to write accounts of events at which they were not present and about which they have not troubled to gain information from those who know the facts. In fact, even in relation to the war that happened recently to us, some have published works under the title of histories without either visiting the sites or going anywhere near the action;… they have given it the name of ‘history’ with the complete shamelessness of a drunk.” [Again Apion 45-47]
• Polybius: “In the same fashion systematic history too consists of three parts,… the second the survey of cities, places, rivers, lakes, and in general all the peculiar features of land and sea and the distances of one place from another,… “ [Histories 12.25e.1]; “So I should say that history will never be properly written, until either men of action undertake to write it (not as they do now, as a matter of secondary importance; … ), or historians become convinced that practical experience is of the first importance for historical composition. Until that time arrives there will always be abundance of blunders in the writings of historians. Timaeus, however, quite disregarded all this. He spent his life in one place, … deliberately renounced all … personal exertion in travel and inspection of localities …” [The Histories 12.28]1
• Dionysius of Halicarnassus (60 BC-7 AD+): “Theopompus [380-315 BC] of Chios… As a student of history he deserves praise on several grounds. … he was an eye-witness of many events, and came in contact with many leading men and generals of his day, whether popular leaders or more cultivated persons. All this he did in order to improve his History.” [Epistula ad cn. Pomeium Geminum (Dionysius to Gnaeus Pompeius) in The Three Literary Letters, trans by Roberts, 6.]
Greco-Roman historiographers, especially around Plutarch’s time (c. AD 100), tended to directly or indirectly try to ground their material in witness approval.
• Anc. historians testify that they did.
• Anc. historians labored to produce witness-based history.
• Anc. historians oft felt 2nd-3rd hand etc. is unacceptable.