CROWN OF THE LAW:
A coronet, usually made of gilded silver, with bells, bearing the Hebrew inscription . It is placed upon the upper ends of the handles of the scroll of the Law. Sometimes the crown is a double one. A similar emblem, often borne between two lions as symbols of strength, decorates the mantle of the scroll and the curtain of the Ark. The device signifies the majestic sovereignty of the Law. It is difficult to say when it was first adopted. In geonic times he who read the last chapter of the Pentateuch on Simḥat Torah had a crown of silver or gold or a garland of myrtle placed upon his head, similar to the one placed upon the head of a bridegroom; whence, probably, the name Bridegroom of the Law. From this arose the custom of having a crown placed permanently upon the scroll of the Law, the making of crowns or garlands on festival days being a transgression of the Law (see Abraham ben Nathan ha-Yarḥi in "Ha-Manhig," Suk. § 59; and R. Nissim to Alfasi, Meg. iii.; Shulḥan 'Aruk, Oraḥ Ḥayyim, 154, 10).
The masters of the school, called "kings" (Giṭ. 62a), were probably the persons originally decorated with the crown of the Law. This seems to be confirmed by the saying of Hillel; "He who makes use of the crown  perishes" (Ab. i. 13). [This "crown" was afterward understood to mean the "crown of God" ( =the Ineffable Name, which was probably engraved upon the crown; see Pirḳe R. El. xlvii.; Targ. Yer. to Ex. xxxiii. 4-6, 25.)] Compare Ab. iv. 5: "Make not the Torah a crown to glory in it." The saying of R. Simon b. Yoḥai concerning the three crowns—the crown of the Law, the crown of the priesthood, and the crown of royalty (see Crown in Post-Biblical Times)—appears also to indicate that the crown of the Law, like the two others, was a material crown, and not a figurative expression like "the crown of a good name." The crown of the Law is probably indicated by the following Haggadah: "When the Israelites before receiving the Law on Mount Sinai proclaimed 'We shall do and hearken!' [Ex. xxiv. 17], there came sixty myriads of angels with two crowns for each—one for each of the two promises; and when they sinned before the Golden Calf there came twice as many demons to take their ornaments away" (Ex. xxxiii. 6; Shab. 88a; compare Pesiḳ. 21 [ed. Friedmann, 102b]; Pesiḳ. de R. K. xiv. 124b; Tan., Teẓawweh, ed. Buber, 50a).
Regarding the question whether the Keter Torah in use may be sold for the purpose of settling a dowry for a daughter, see Isaac Lampronti, "Paḥad Yiẓaḳ," letter מ, 170b.