Before talking about the historical data of international relations, it is necessary to briefly introduce the greatest modern historian to date, Leopold von Ranke, in a methodological sense, together with the modern and contemporary methods of collecting and textual investigation of historical data, which he established as the primary founder. Micro-exploration is very important. Microhistorical inquiry, which relies on rigorous attitude, strict procedure and necessary intelligence, forms the cornerstone and a large part of the content of historical research, and its main method is the fundamental method of modern historiography. The establishment of this method, and even the establishment of modern history itself, is closely linked to Ranke. Rank’s primary contribution to historiography and historiography was the creation of the primary scientific method of modern historiography, based strictly on contemporaneous sources (especially archival sources), together with a major innovation in the method, the critical examination of historical sources. In other words, he established the principle of using contemporaneous data, especially archival historical data, as the basis of historical research, and established the basic method of scientific research of historical data. On the other hand, Rank was responsible for the great turning point of the historiography revolution, as the great historian Gooch put it, “when he began to write, the eminent historians believed that memoirs and Chronicles were the primary authoritative sources.” By the time he had finished writing, every scholar whose reputation was yet to be established, or whose reputation might be discredited, had learned that it was necessary to rely at least on the documents and letters of the subjects themselves and of those who had direct contact with the events they recounted.” [1] In the latter, he may be said to have established a science of historical evidence by analyzing the sources left by authors, whether contemporary or later, in terms of their personal purport, social connections, and the likelihood of their knowledge of historical events, and by comparing them with relevant sources written by others. On the basis of the above fundamental methods he established, and especially on the basis of the extensive excavation and application of the archival materials of many countries, Rank faithfully reproduced the political history of Central and Western Europe, especially the political history of the great powers of Central and Western Europe.

The first principle of the modern and contemporary methods of collecting historical materials pioneered by Rank is to collect as much as possible the original archival historical materials stored in public and private archival storage places or storage institutions, that is, the most important “first-hand” historical materials. More generally, before and during the study of a historical subject, it is necessary to determine comprehensively and precisely what kind of historical materials are needed, what specific categories of historical materials they belong to, and to distinguish and combine the principal and secondary ones among them; Then, it is necessary to investigate the specific places where the required historical data can be found, and then try to excavate and collect. For unpublished sources, the archival sources mentioned above, it is first necessary to know whether they have been declassified, that is, whether they are accessible (in many cases, what is available to researchers and what is not); In the case of archival materials that are already accessible, attention and detailed information about their preservation, concentration and classification and access procedures are required. For historical materials that have already been published, such as collections of official archival documents edited and published by the government, or public documents edited and published by non-governmental organizations or individuals, or memoirs, letters, diaries, etc., of persons concerned, if bibliography has already been compiled in the subject area to be studied or closely related to it, Familiarity with bibliography is often required. The textual research of historical materials means the identification of the nature of historical materials and its value as historical evidence. textual criticism can be divided into two aspects: the former is the revision and discrimination of falsification, or “textual criticism”, while the latter is about whether the historical facts described in the historical materials are credible and accurate, or to what extent. No matter what kind of historical documents, we must try our best to have a deep understanding of the source of information and personality of the author. In particular, in the case of so-called secondary sources, i.e., historical instruments which are not direct witnesses of historical events (i.e., the parties themselves and those who have direct contact with the events they recount), whether they are based primarily on primary sources or not, whether they are contemporary writings or later historical studies or accounts, It is necessary to examine the author’s understanding of the historical events described by the direct witnesses and his ability to accurately record them.

According to the decreasing order of their original degree (or, in a sense, their importance), the historical materials of international relations can be divided into the following six categories: (1) unpublished archival historical materials; (2) Published archival historical materials; (3) Official history; (4) Public documents; (5) Memoirs, collections of letters, published diaries, newspaper reports or reviews at the time, etc.; (6) Secondary materials (books and articles).

In general, apart from the absolute superiority of the first two types of historical materials, namely unpublished and published archival historical materials in terms of importance and even reliability, the value of the other types of historical materials mentioned above is relative to each other and varies according to different specific occasions. For example, there can be memoirs, letters, and diaries that have been rigorously researched or judged by common sense to be of high historical value (higher than some official histories and public documents), and there can be such documents that are not, or even very unreliable. For example, the quality of secondary sources can vary greatly, among which monographs based mainly on primary sources can be vastly superior to general reviews based mainly on other secondary sources, and many works belonging to the former category, subject to rigorous examination or widely recognized by the relevant historians, can be regarded as superior in historical value to some historical sources that are higher in the above order. The same is true of official history. There are also official histories with very detailed and reliable historical materials and fair and objective historical theories, and those with thin and one-sided historical materials that are intended to whitewash the past or pursue other improper purposes. In short, in addition to the basic principle of collecting and using as much archival data as possible, most of the rest must be based on the specific historical situation in which the specific research task is located.

Unpublished archival materials can be official or private documents. The former category refers to unpublished archival documents that are generally stored, owned and disposed of by official institutions, while the latter category refers to unpublished archival documents that are generally stored by private or official institutions, but whose ownership and disposition are exclusively private. In recent years, due to the development of historiography and archival methods, a new category of unpublished archival materials has emerged, that is, oral records recalling historical events or processes, but their quantity, importance and general reliability are far less than that of official and private documents described here. Therefore, relatively speaking, it is especially necessary to be verified.

Before talking about the historical data of international relations, it is necessary to briefly introduce the greatest modern historian to date, Leopold von Ranke, in a methodological sense, together with the modern and contemporary methods of collecting and textual investigation of historical data, which he established as the primary founder. Micro-exploration is very important. Microhistorical inquiry, which relies on rigorous attitude, strict procedure and necessary intelligence, forms the cornerstone and a large part of the content of historical research, and its main method is the fundamental method of modern historiography. The establishment of this method, and even the establishment of modern history itself, is closely linked to Ranke. Rank’s primary contribution to historiography and historiography was the creation of the primary scientific method of modern historiography, based strictly on contemporaneous sources (especially archival sources), together with a major innovation in the method, the critical examination of historical sources. In other words, he established the principle of using contemporaneous data, especially archival historical data, as the basis of historical research, and established the basic method of scientific research of historical data. On the other hand, Rank was responsible for the great turning point of the historiography revolution, as the great historian Gooch put it, “when he began to write, the eminent historians believed that memoirs and Chronicles were the primary authoritative sources.” By the time he had finished writing, every scholar whose reputation was yet to be established, or whose reputation might be discredited, had learned that it was necessary to rely at least on the documents and letters of the subjects themselves and of those who had direct contact with the events they recounted.” [1] In the latter, he may be said to have established a science of historical evidence by analyzing the sources left by authors, whether contemporary or later, in terms of their personal purport, social connections, and the likelihood of their knowledge of historical events, and by comparing them with relevant sources written by others. On the basis of the above fundamental methods he established, and especially on the basis of the extensive excavation and application of the archival materials of many countries, Rank faithfully reproduced the political history of Central and Western Europe, especially the political history of the great powers of Central and Western Europe.

The first principle of the modern and contemporary methods of collecting historical materials pioneered by Rank is to collect as much as possible the original archival historical materials stored in public and private archival storage places or storage institutions, that is, the most important “first-hand” historical materials. More generally, before and during the study of a historical subject, it is necessary to determine comprehensively and precisely what kind of historical materials are needed, what specific categories of historical materials they belong to, and to distinguish and combine the principal and secondary ones among them; Then, it is necessary to investigate the specific places where the required historical data can be found, and then try to excavate and collect. For unpublished sources, the archival sources mentioned above, it is first necessary to know whether they have been declassified, that is, whether they are accessible (in many cases, what is available to researchers and what is not); In the case of archival materials that are already accessible, attention and detailed information about their preservation, concentration and classification and access procedures are required. For historical materials that have already been published, such as collections of official archival documents edited and published by the government, or public documents edited and published by non-governmental organizations or individuals, or memoirs, letters, diaries, etc., of persons concerned, if bibliography has already been compiled in the subject area to be studied or closely related to it, Familiarity with bibliography is often required. The textual research of historical materials means the identification of the nature of historical materials and its value as historical evidence. textual criticism can be divided into two aspects: the former is the revision and discrimination of falsification, or “textual criticism”, while the latter is about whether the historical facts described in the historical materials are credible and accurate, or to what extent. No matter what kind of historical documents, we must try our best to have a deep understanding of the source of information and personality of the author. In particular, in the case of so-called secondary sources, i.e., historical instruments which are not direct witnesses of historical events (i.e., the parties themselves and those who have direct contact with the events they recount), whether they are based primarily on primary sources or not, whether they are contemporary writings or later historical studies or accounts, It is necessary to examine the author’s understanding of the historical events described by the direct witnesses and his ability to accurately record them.

According to the decreasing order of their original degree (or, in a sense, their importance), the historical materials of international relations can be divided into the following six categories: (1) unpublished archival historical materials; (2) Published archival historical materials; (3) Official history; (4) Public documents; (5) Memoirs, collections of letters, published diaries, newspaper reports or reviews at the time, etc.; (6) Secondary materials (books and articles).

In general, apart from the absolute superiority of the first two types of historical materials, namely unpublished and published archival historical materials in terms of importance and even reliability, the value of the other types of historical materials mentioned above is relative to each other and varies according to different specific occasions. For example, there can be memoirs, letters, and diaries that have been rigorously researched or judged by common sense to be of high historical value (higher than some official histories and public documents), and there can be such documents that are not, or even very unreliable. For example, the quality of secondary sources can vary greatly, among which monographs based mainly on primary sources can be vastly superior to general reviews based mainly on other secondary sources, and many works belonging to the former category, subject to rigorous examination or widely recognized by the relevant historians, can be regarded as superior in historical value to some historical sources that are higher in the above order. The same is true of official history. There are also official histories with very detailed and reliable historical materials and fair and objective historical theories, and those with thin and one-sided historical materials that are intended to whitewash the past or pursue other improper purposes. In short, in addition to the basic principle of collecting and using as much archival data as possible, most of the rest must be based on the specific historical situation in which the specific research task is located.

Unpublished archival materials can be official or private documents. The former category refers to unpublished archival documents that are generally stored, owned and disposed of by official institutions, while the latter category refers to unpublished archival documents that are generally stored by private or official institutions, but whose ownership and disposition are exclusively private. In recent years, due to the development of historiography and archival methods, a new category of unpublished archival materials has emerged, that is, oral records recalling historical events or processes, but their quantity, importance and general reliability are far less than that of official and private documents described here. Therefore, relatively speaking, it is especially necessary to be verified.