John I, originally John Kurkuasz Tzimiskes (Greek: Ιωάννης Α΄ Τζιμισκής, Latin: Ioannes I Tzimisces, 924 - Constantinople, January 10, 976) was the emperor of the Byzantine Empire. He ruled from 11 December 969 until his death. He was II. The murderer of Phókasz Nikéhorosz. Ióannesz Kurkuasz came from a Cappadocian aristocratic family of Armenian origin that produced famous generals. Through his mother, he was the nephew of Nikéhorosz Phókasz, who belonged to a similarly rich and successful family. His military career was still in VII. It started during the time of Constantine, who appointed him governor of Armenia thema at a surprisingly young age. In this capacity, in 956 he took the castle of Szamoszata on the Mesopotamian border. After Nikéhorosz's accession to the throne in 963, which he also supported, he was promoted to the rank of Domesticos to the commander-in-chief of the eastern theater and was part of the emperor's triumphs over the Muslims. The young, successful, attractive manner and appearance Ioannes also impressed the empress Theophano, who eventually became his lover. he did and organized an assassination attempt against Nikéhorosz. The murder was committed by Ióannes and his friends on the night of December 11, 969. Under the new government, the Patriarch of Constantinople Polüeuktés used Ióannes to strengthen the positions of the church. He obliged him to do public penance, punish his accomplices and banish Theophano. Ioannes was forced to allow him to enter the church and be crowned by the patriarch. At the same time, Polüeuktes abolished the law of Nikéhoros, which, in order to protect the revenues of the treasury, prohibited the founding of new church institutions and the donation of land to the clergy. During the reign of Ióannés, like his predecessor, he achieved great military successes, further strengthening the empire. Its popular nickname, Tzimiszkész, is of Armenian origin and means: red boot.

Emperor Ioannes Tzmiszkesz ruled from 969-976, and his coinage was significant in many ways. Tzmiszkesz significantly increased the coinage. This is due to the growth of the economy and the strengthening of the imperial power. Tzmiszkész renewed the Byzantine coinage traditions. This included the restoration of the designs of classical Roman coins, as well as the issuance of new, more modern coins. Its coins are the Solidus, which was the main currency of the Byzantine Empire. The solidus of Tzmiszkész were made of gold and minted on the model of the classical Roman solidus.Tremissis, it was the second most important currency of the Byzantine Empire. Tzmiszkész's tremissis were made of silver and modeled after the classic Roman tremissis. Demiss, it was the third most important currency of the Byzantine Empire. Tzmiszkész's demisses were made of silver and minted on the model of classical Roman demisses. Follis, this was the smallest currency of the Byzantine Empire. Tzmiszkész's follis were made of copper. Tzmiszkész's coinage included many technical innovations. These included the use of better quality metals and the use of finer processing techniques. The coinage of Tzmiszkész was one of the most important periods in Byzantine monetary history. The emperor contributed significantly to the stability of Byzantine finances and the international prestige of the empire.