成立于1864年的第一国际是马克思和恩格斯亲自领导的政党性国际工人组织，在国际共产主义运动史上具有划时代的意义。它不仅使欧洲在1848年革命失败后再次掀起革命浪潮，而且使科学社会主义思想在整个欧洲乃至北美洲都传播开来。共产主义理想信念不仅是无产阶级政党发生发展的精神源泉，也是无产阶级政党担负历史使命的力量支撑。第一国际的兴起与发展离不开工人阶级的团结与斗争，同样也离不开对共产主义理想信念的执著。马克思和恩格斯作为第一国际的领导者与实践者，深刻影响了第一国际的思想方向和信仰选择。从理想信念角度研究马克思恩格斯第一国际时期的历史活动，深刻揭示马克思恩格斯对第一国际共产党人思想和信仰发展历程的作用和影响，是以史为鉴，以史为镜进行新时代共产党人理想信念建设的题中应有之义。

本文以第一国际时期马克思恩格斯对共产党人理想信念的建设为研究对象，运用文献研究法、文本分析法和历史分析法等研究方法，在学界现有的研究基础上，深刻分析第一国际时期马克思恩格斯坚定共产党人理想信念的历史背景、历史过程及历史经验，以期为新时代中国共产党人理想信念建设提供有益经验。全文共分为四章：

第一章主要从国际工人协会所处历史时期的社会现实状况、国际共产主义运动发展实际以及工人阶级思想发展状况三个层面进行研究分析，以此来阐明第一国际时期马克思恩格斯坚定共产党人理想信念的历史背景。

第二章重在梳理第一国际时期马克思恩格斯坚定共产党人理想信念的历史轨迹。本章按照时间顺序将第一国际时期马克思恩格斯坚定共产党人理想信念的历史活动分为：1863.7-1866.9的第一国际创立时期，这是马克思恩格斯通过组建第一国际，拟定《成立宣言》和《章程》实现共产党人理想信念聚合的过程；1866.9-1869.9的第一次日内瓦代表大会到巴塞尔代表大会时期，这是马克思和恩格斯与蒲鲁东主义、巴枯宁主义正面交锋并取得胜利，实现共产党人理想信念深入发展的时期；1869.9-1872.9的巴塞尔代表大会之后到伦敦代表会议时期，这是共产主义理想在实践中大放光芒，获取最终胜利的时期；1872.9-1876.7的国际最后年代，这是马克思恩格斯通过海牙代表大会重申共产主义理想信念，推动各民族国家无产阶级政党建立，实现理想信念新发展的时期。

第三章旨在总结第一国际时期马克思恩格斯坚定共产党人理想信念的历史经验。马克思恩格斯通过发展理论和思潮批判使共产党人保持理论上的清醒；通过使无产阶级意识提升、历史使命坚定、国际主义精神发扬以及组织上忠诚团结的保持四个方面使理想信念建设的内容更加具体；通过采取团结与斗争相适应、理论与实践相统一、坚决与温和相结合的方式使理想信念建设策略创新，这成为后世共产党人坚定理想信念的宝贵经验。

第四章主要从夯实理想信念建设的理论、内容和领导基础；在勇于斗争和思潮批判中坚定理想信念；锻造理想信念建设的组织、媒介和实践载体；完善理想信念建设的制度、舆论和环境保障等四个方面论述了第一国际时期马克思恩格斯坚定共产党人理想信念对新时代的启示。

The First International, founded in 1864 and led by Marx and Engels, was a political international workers' organization that had epoch-making significance in the history of the international communist movement. It not only revived the revolutionary wave in Europe after the failure of the 1848 Revolution but also spread the scientific socialist ideas throughout Europe and even North America. The idealistic belief in communism was not only the spiritual source of the birth and development of the proletarian party but also the strength supporting the historical mission of the proletarian party. The rise and development of the First International were inseparable from the unity and struggle of the working class, as well as their persistence in the idealistic belief of communism. As leaders and practitioners of the First International, Marx and Engels profoundly influenced the ideological orientation and faith choices of the First International. A study of Marx and Engels' historical activities during the First International period from the perspective of idealistic belief would reveal their role and influence in the ideological and faith development of the First International's communists. This has significant implications for the idealistic belief construction of new-era communists through the lessons of history.

This paper focuses on the role of Marx and Engels in the construction of the idealistic belief of the Communist Party during the First International period. Utilizing research methods such as documentary analysis, textual analysis, and historical analysis, the paper delves deeply into the historical context, processes, and experiences that contributed to the firm establishment of the idealistic belief of the Communist Party during the First International period. The aim is to provide valuable insights for the construction of idealistic belief among Chinese Communist Party members in the new era, based on the existing research in the field. The paper is divided into four parts:

Chapter One primarily focuses on analyzing the historical context of the International Workingmen's Association (also known as the First International) from three perspectives: the social reality of the period, the actual development of the international communist movement, and the intellectual development of the working class. This is done in order to shed light on the historical background that contributed to the unwavering communist ideals of Marx and Engels during the First International.

Chapter Two focuses on tracing the historical trajectory of Marx and Engels' unwavering the idealistic belief of communism during the first International. This chapter analyzes the historical events that shaped their unwavering conviction in the communist cause, arranged chronologically into four periods: the founding period of the First International from July 1863 to September 1866, during which Marx and Engels formed the International and developed the Communist ideals through drafting the "Declaration of the International" and the "Statutes"; the period from the First Geneva Congress to the Basel Congress from September 1866 to September 1869, during which Marx and Engels confronted and ultimately defeated Proudhonism and Bakuninism, and further developed the Communist ideals; the period from the Basel Congress to the London Congress from September 1869 to September 1872, during which Communist ideals shone brightly in practice and ultimately triumphed; and the final years of the International from September 1872 to July 1876, during which Marx and Engels reaffirmed their faith in Communist ideals at the Hague Congress and worked towards establishing proletarian political parties in various countries, thus paving the way for the new development of Communist ideals.

Chapter Three aims to summarize the historical experience of Marx and Engels in maintaining the ideals and beliefs of communist party members during the First International period. Through the development of theory, criticism of trends, and enhancing proletarian consciousness, historical mission, internationalism, and organizational unity, Marx and Engels made the construction of ideals and beliefs more concrete. They also innovatively adapted strategies to unite and fight, unite theory and practice, and be resolute and moderate, which became valuable experiences for future communist party members to maintain their ideals and beliefs.

Chapter Four mainly discusses the enlightening influence of Marx and Engels' unwavering communist ideals and beliefs during the First International period on the new era, from four aspects: solidifying the theoretical foundation, content, and leadership of ideal and belief construction; firmly maintaining ideals and beliefs through courageous struggle and trend criticism; forging organizational, media, and practical carriers for ideal and belief construction; and improving the system, public opinion, and environmental protection guarantee for ideal and belief construction.