The Luther seal or Luther rose is a widely-recognized symbol for Lutheranism. It was the seal that was designed for Martin Luther at the behest of Prince John Frederick, in 1530, while Luther was staying at the Coburg Fortress during the Diet of Augsburg. Lazarus Spengler, to whom Luther wrote his interpretation below, sent Luther a drawing of this seal. Luther saw it as a compendium or expression of his theology and faith, which he used to authorize his correspondence. Luther informed Philipp Melanchthon on September 15, 1530 that the Prince had personally visited him in the Coburg fortress and presented him with a signet ring, presumably displaying the seal.