The material of the memorial plaque is symbolically porphyry from the Saxon town of Rochlitz, where Johann Mathesius was born. It was brought ceremoniously in 1965 on the anniversary of his death by an evangelical pastor from Rochlitz. Carved on the plaque is:
This plaque is dedicated in memory of Martin Luther's associate and friend Johann Mathesius, a Jáchymov pastor, * 24. 6. 1504 in Rochlitz, Saxony, † 7. 10. 1565 in Jáchymov, on the 400th anniversary of his death, by his home congregation.
Saxony and the adjacent Erzgebirge were traditionally Lutheran before the period of forced recatholization after the end of the Thirty Years' War. Even the Jáchymov estate, which was founded by the Šlik Count family, subscribed to the Evangelical faith and the church of St Jáchym became Catholic only during the Counter-Reformation. Mathesius was one of the great humanists. During his first stay in Jáchymov in 1532-1540, he served as the rector of the famous local Latin school, whose level he significantly raised and founded a library that has been preserved to this day. Even then he was influenced by the important reformer Martin Luther, who worked at the University of Wittenberg, where Mathesius completed his studies. There he became so close to Luther that he is traditionally referred to as his associate and was also his first biographer. He worked as a preacher in Jáchymov from 1542 until his death. We do not know the exact place of his grave because it was destroyed during the Counter-Reformation and his remains were scattered somewhere below the town. In his sermons, he addressed mainly local miners and tried to introduce them to new knowledge and advances in technology, as well as appealing to their morality and honesty in work matters. The sermons are summarized in the book Sarepta or The Miner's Postil (Sarepta was a biblical mining town). The Sarepta in Czech translation and other information about Mathesius' life can be found in a small memorial hall inside the church, which was curated by the Paláns from the local evangelical congregation.
The Church of our Saviour itself was built by the local Augsburg congregation in 1904 – on the 400th anniversary of Mathesius' birth. The north side of the church is decorated with medallions of Martin Luther and Johann Mathesius. The stained-glass windows, which also depict Luther and Mathesius, are another distinctive decorative element.
