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 flat, 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-flat major, RV 359 Concerto No. 8 in D minor, RV 238 Concerto No. 9 in B-flat 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