元代官帽 神似香爐蓋 帽頂假借爐頂 Yuan Dynasty official hats and censer covers looked alike.

 

From Song Dynasty on, the top of censer cover was decorated with a jade. 

[Song Dynasty]
[Yuan Dynasty]
[Ming Dynasty]
[Qing Dynasty]
The design inspired  鈸笠帽.
[鈸笠帽]
鈸笠帽 was the Yuan Dynasty official hat.
[Emperor 元成宗] [Emperor 元寧宗]

Although 鈸笠帽 was named after cymbal, the hat top was with jade, it looked like a censer cover more than a cymbal.
[Emperor 元仁宗]
Mongolians left for yurts on Mongolian steppe and marched for China in 13th century.  
Even though they overthrew Song Dynasty and established Yuan Dynasty, they still lived under heaven.
Both hats and sedan chair roof looked like tiny cosmos.
Wherever Mongolian adventured, they always believed in that they were being under the round sky and above the square earth.

參考文獻：
*國立故宮博物院(台北) Open Data 
*北京服裝學院 民族服飾博物館
*元仁宗肖像圖
*元寧宗肖像圖
*元成宗肖像圖
*元 王世英墓 陶俑
*榆林石窟 第六窟壁畫《男供養人》
*《蒙古軍團圖》引自 “史集 Jami‘al-Tarikh”(蒙古伊兒汗國史書),  Rashid al-Din(1247～1317).