# Notation used for harmonic context

Could someone please explain what it means to say, "the harmonic context of V/V-V-I".

How should one read this? It would be nice if you could also give two or three examples if you think it would help understand this better.

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That is a roman numeral analysis of harmony where I is the tonic chord of a key, V is the dominant chord of a key and V/V is a secondary dominant. This secondary dominant functions as a dominant of a dominant chord and is outside the key.

For example in the key of C major this progression would look like this : `D - G - C`. D major is not in the key of C, but functions as a dominant chord to the G.

In the key of G major this progression would look like this : `A - D - G`. A major is not in the key of C, but functions as a dominant chord to the D.

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I feel that II-V-I makes more sense. V/V is, as Dom says, the secondary dominant, or 'dominant dominant'. There is no confusion here. If the sequence was ii-V-I, then the chords would be (in C) Dm-G-C, as Dmaj. is not contained within the key of C. However, what if the sequence was (and sometimes is) A-D-G-C ? Would the Roman numerals have to go V/V/V-V/V-V-I? It starts to get unwieldy. What simpler than VI-II-V-I ? Capitals for maj.,as opposed to lower case for min.Rather like the NNS.

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Isn't it possible that ii can be confused with a C#? Or is that not a possibility? – user1953384 Jun 10 '14 at 12:22
You are right that in sequences Roman numerals get hairy as you get more out of the key, but the progression in your example is actually less complicated than that. It would be `V/ii - V/V - V - I`. – Dom Jun 10 '14 at 12:44
@user 1053384 - no chance at all. That would be either I# or IIb. The basic numerals always refer to the basic scale notes and the chords that are spawned from them. – Tim Jun 10 '14 at 17:18
@Dom - I get your point, but when I'm in a particular key, I think in that key, not in other related keys. Isn't that the point of stating a key anyway ? – Tim Jun 10 '14 at 17:21