The Talmud in יומא page 72b, discusses the specialness of Torah study provided that it comes with יראת שמים, fear of Heaven. The Gemara notes that in the Beit Hamikdash, there were three vessels that had gold lattice type work on them. They looked like golden crowns on each of these vessels.
The golden crown was placed on the שלחן, the table of the showbread, as a symbol of wealth attributed to the Jewish king. This was the כתר מלוכה, the crown of the kingdom. (There is a wedding hall in Jerusalem called שלחן דוד.)
The second crown was on the small altar known as מזבח הקטורת. This symbolized the work of the Kohanim in the Temple, and the כתר כהונה. It also alluded to the twenty four gifts that the Kohein received as he performed his special role.
The third crown was on the ארון קדש, symbolizing the Torah and the כתר תורה. The Rabbis said that the כתר מלכות was reserved for kings of Davidic descent. The כתר כהונה was reserved for the descendants of Aaron. But the כתר תורה is available to all who wish to partake of it with diligence and sincerity.
It is also worth noting that in פרקי אבות it's written that the כתר שם טוב, the crown of a good name, rises above all three.