D Major is a key of Tongeschlechts major, which is based on the root d. The key of D major is written in the notation of two sharps ( F sharp, cis). The corresponding scale and the basic chord in this key ( the tonic d- F #-A ) will be denoted by the term D major.
D major is considered the most festive among the keys. This has to do with the fact that in times of Baroque music Baroque trumpets sounded on festive occasions, were mostly tuned to D.
In addition, D major is the most common key in Irish folklore, as the traditional Irish instruments are tuned (eg, the uilleann pipes ) in D. Also on the violin can play this key quite easily.