Gury Rugotin, the saint, the first archbishop of Kazan, hailed from the nobility of the former town of Radonezh, was known in the world as Gregory. At a young age, Grigory joined the service of Prince Ivan Penkov. The prince was so pleased with him that he entrusted him with the management of the entire house. But this power of attorney did not last long. Other servants of the prince, out of envy for Gregory, slandered him that he was in a criminal relationship with the princess. Annoyed by the false accusation, the prince ordered Gregory to be put in a dungeon, deliberately set up in a deep-dug pit. The innocent sufferer languished there for two years, because after two years the prisoner's door opened freely. 
Recognizing his salvation as God's Providence, he renounced the world and set out on his way to the monastery of St. Joseph of Volokolamsk. There he clothed himself in the robes of a monk, taking the name Guria, and was soon appointed (1522) abbot of the monastery; then he was transferred to the Selizharov monastery, and on February 3, 1555, he was consecrated archbishop of the new Kazan diocese. Gury established two monasteries there for the education of Christian and pagan children; in addition, under his special supervision, he built a stone cathedral in the name of the Annunciation of the Blessed Virgin Mary. Caring for his flock, Saint Gury multiplied it by converting many Mohammedans to the Christian faith. He passed away on December 4, 1563, having accepted the schema two days before his death.
In 1630, the relics of St. Gury, found on October 4, 1595, were transferred from the Transfiguration Monastery of the Savior to the Cathedral of the Annunciation in Kazan. Since 1918, they have been in the Kazan Bogoroditsky Monastery, then in the parish church of Paraskeva Friday, in the Peter and Paul Cathedral, and since the mid-1930s they have been moved to the Churches of the Holy Princes Theodore, David and Konstantin, the Yaroslavl Wonderworkers at the Arsky cemetery, where they are currently located.
Guriy began the diocese in Kazan. By decree of Tsar John Vasilyevich, Metropolitan Macarius established the third-degree archbishopric of Kazan in 1555. After the archbishops, there were metropolitans from 1589, and after them bishops and archbishops from 1832. At first, the diocesan bishops were called Kazan and Astrakhan; then, from 1602, Kazan and Sviyazhsk, and from 1799 Kazan and Simbirsk. In 1799, the vicar diocese of Kazan was established; its bishops were ordered to be written Sviyazhsk; but in 1802, the Kazan vicariates were abolished.