Christian IV was the king of Denmark from 1588 until 1684. His reign of 59 years was the country’s longest. The crown of Christian den Fjerde is showcased among other Danish Crown Regalia in a basement vault of The Treasury located in Rosenborg Castle. The crown was crafted by Didrik Fyren in 1596. The gold, cut diamonds, pearls and other gemstones weigh about 6.4 pounds.