Classical concerto Allegro has been viewed either as an independent form that incorporates form-functional elements of the baroque ritornello form and the classical sonata form, or as one of the specific types of the classical sonata form. Regardless of the definition, however, it is generally acknowledged that the first movement form of the late-18th-century concerto differs in a number of ways from that of a sonata or a symphony. The present study focuses on one of the most characteristic regions of that form, the subordinate key area of the exposition, where the subordinate theme or group of themes is, usually after a full authentic cadence, followed by a specific display episode (bravura theme). The latter falls with a characteristic trill-cadence into a subordinate-key ritornello. The 19th-century repertoire is reach in interesting compositional reinterpretations and transformations of this typical classical design. The paper points to some general tendencies in the subordinate key areas of romantic concertos and presents a more detailed analysis of this area in the first movements of Tchaikovsky`s Violin Concerto in D major and Brahms`s Double Concerto in A minor.