The basement of Rosenberg Palace has been a heavily guarded national treasure since ancient times, and the Royal Danish Guard guards priceless treasures 24 hours a day: royal symbols such as crown, scepter, king's sword and royal jewels. This underground treasure room was first opened to the public on 1975. The treasure room is divided into three rooms, which are classified in chronological order: the first room mainly displays the treasures before Christian IV; The second room mainly displays the treasures of Christian IV and his son Frederick III. The third room mainly displays the royal treasures from Christian V to 1849, including the crown of Christian V and the treasures of the town hall of Rosenberg Palace.

The crown decorated with diamonds and jewels is a symbol of the supremacy and absolute dignity of Danish kingship. The oldest Danish crown can be traced back to 1596. It is the crown of Christian IV, pure gold crown, with gold hoop, inlaid with enamel and precious stones, and weighs about 3 kilograms. Frederick III, the son of Christian IV, also used this crown when he was crowned. The crown of Christian V is the most famous in the Danish Wang Guanzhong in Rosemburg's collection. Today, the royal Danish coat of arms and the crown pattern on the Danish national emblem all come from this crown.

In the past, the king of Denmark was nominally elected by the nobility, but the reality is that the final winner is often the eldest son of the king. Until 1660, Frederick III abolished the aristocratic election system and implemented absolute monarchy. The throne is directly inherited by the king's eldest son. Later, Frederick III decided to build a new crown for his son, later Christian V. From the coronation of Christian V in 167 1 year to the abolition of absolute monarchy in Denmark in 1849, every Danish king used this crown.

This crown is made of gold and weighs more than 2 kilograms. The main structure is a pure gold circular closed bracket, and finally converges to the top sphere from bottom to top. The design was inspired by the crown of King Louis XIV of France, symbolizing the permanence and majesty of monarchical power. A small cross stands at the top of the sphere at the top of the crown, indicating that the divine right of the monarch and the power of the church were higher than the royal power at that time. Diamonds and priceless gems crisscross the crown. At the top of the cross is a rare sapphire with ruby stripes. The crown is inlaid with a huge and dazzling square sapphire, which was given to Danish King Christian 1 by the Duke of Milan in 1474. Below the gem is the word "Christian V" embroidered with gold thread. After Denmark abolished the absolute monarchy in 1849, the coronation ceremony with a crown was also cancelled, but the crown was still used when the monarch died. In the ceremony before cremation after the death of the king, the crown is placed on the coffin containing the king's body. The crown was last used in 1972, at the funeral of Frederick IX, the father of the current Danish Queen Margrethe II.