La cetra, Op. 9, is a set of twelve violin concertos by Antonio Vivaldi, published in 1727. All of them are for violin solo, strings, and basso continuo, except No. 9 in B♭, which features two solo violins. The set was named after the cetra, a lyre-like instrument, and was dedicated to Emperor Charles VI.
La cetra is also the title given to another set of twelve violin concertos by Vivaldi which was never published. This set is almost entirely different from the published set, sharing only one concerto and one concerto movement. Like the published set, it was dedicated to Emperor Charles.
List of concerti
Concerto No. 1 in C major, RV 181a
Concerto No. 2 in A major, RV 345
Concerto No. 3 in G minor, RV 334
Concerto No. 4 in E major, RV 263a
Concerto No. 5 in A minor, RV 358
Concerto No. 6 in A major, RV 348
Concerto No. 7 in B♭ major, RV 359
Concerto No. 8 in D minor, RV 238
Concerto No. 9 in B♭ major, RV 530
Concerto No. 10 in G major, RV 300
Concerto No. 11 in C minor, RV 198a
Concerto No. 12 in B minor, RV 391