The Prophet Muhammad, of Arab origin, spent his life in the Arabian Peninsula. It is widely believed that his initial followers were predominantly of Arab descent. However, it is crucial to note that Muhammad is regarded as the final prophet, sent as a messenger to invite all of humanity to follow Allah. Consequently, it is not uncommon for individuals of non-Arab backgrounds to embrace Islam and believe in his message. In this study, the personalities of “Byzantine origin” or “Rûmî/ Rûmî origin” as the Arabs call them, who met the Prophet and became Muslims and gained the qualification of being a Companion, were investigated, their identities were determined and information about their lives was given, with special emphasis on whether they narrated hadith or not. The primary objective is to identify these individuals, provide information about their lives, and emphasize whether they were involved in narrating hadiths. It is noteworthy that there has been no independent study conducted on the subject of “Roman/Byzantine Companions” to date. To facilitate a comprehensive examination and establish a robust foundation for evaluation, it is imperative to offer brief insights into both Arab and Roman/Byzantine contexts. This includes exploring relations between the Arabian Peninsula and the Roman/Byzantine Empire. The research commences by providing information on “Arabian Peninsula - Roman/Byzantine Empire Relations,” with a primary emphasis on the relations during the Prophet’s era. The study aims to elucidate how individuals of Roman/Byzantine descent came to the Arabian Peninsula, laying the groundwork for a more nuanced understanding of this historical context. Individuals of Roman/Byzantine origin residing in the Arabian Peninsula arrived through diverse means. Many were brought in as slaves and established a permanent presence in the region. Additionally, there were those who chose to settle here, driven by motivations such as practicing their professions, spreading Christianity, and engaging in commercial endeavors. Notably, certain Romans/Byzantines who encountered the Prophet in Mecca were blacksmiths, while those in Medina included carpenters and merchants. To address the question of whether individuals of Roman/Byzantine origin who embraced the Prophet would be classified as Companions, it became imperative to establish a clear definition of the term “Companion”. A dedicated section was created for this purpose, where in individuals meeting this defined criterion were assessed and recognized as Companions. Those identified as companions were then listed alphabetically, accompanied by biographical information extracted from various sources, including hadith, tafsir, sira, tabaqât, and Islamic history. It is worth noting a specific aspect during this review. While examining Islamic sources that provide insights into the lives of the Companions, numerous names were discovered that deviated from customary Arabic nomenclature and were identified as of Roman/ Byzantine origin. Examples include Nestas (Anastas), Mina (Minas), and Yuhannes (Yoanis). Despite the likelihood that bearers of such names were slaves and potentially of Roman/Byzantine heritage, the absence of explicit evidence precludes their inclusion among the Companions of Roman/Byzantine origin. There were also people of Roman/ Byzantine origin who lived during the Prophet’s time and converted to Islam but were unable to meet him. It is seen that these people, who are called Mukhadrams, are mistakenly considered as Companions in some sources. In order to prevent this confusion and to distinguish between those who were Companions and those who were not, the Mukhadrams are analyzed under a separate heading, and those whose names are identified are introduced here with brief biographical information. The article introduces an individual who, despite not being a Companion of Roman/ Byzantine origin, has made such a claim, leading to significant revelations. A key finding dispels the notion held by some, particularly in the West, that the Prophet was exclusively “the prophet of the Arabs”. The research substantiates this by establishing that seven individuals of Roman/Byzantine origin encountered the Prophet, embraced Islam, and became Companions, disproving the misconception. Among these seven, six were men and one was a woman. The study further discerns that Roman/Byzantine descendants who migrated to the Arabian Peninsula, adopted Islam, and became Companions were predominantly skilled artisans, including blacksmiths, carpenters, and construction masters. It appears that many of them arrived or were brought to the region for the purpose of practicing their respective professions. Additionally, the research notes that due to factors such as their status as slaves and language barriers, individuals of Roman/Byzantine origin did not actively transmit hadiths from the Prophet. Consequently, it is established that they did not significantly contribute to the dissemination of scientific knowledge during that historical period.