EPTMovement I. Allegro vivace
An introduction to the sonata-allegro form.
Mendelssohn started composing this symphony while traveling in Italy between 1830 and 1831. It is numbered four because it was published posthumously, but it was completed third. I want to share the first movement with you today and introduce the sonata-allegro form. It might seem technical if you haven't studied music, but I'll try to make it easy to follow. The goal is to simply and briefly show how themes and forms are used.
In music, there are two great principles. The first is to not be boring. This means varying your melodies, textures, etc. The second is to be comprehensible. This means not varying too much, and to repeat important themes. The ear also likes to hear pleasing melodies repeated. The sonata-allegro form is a musical structure commonly used since around Beethoven's time whose popularity endured probably because it accomplishes these two points while maintaining great flexibility.
Essentially the sonata-allegro is a ternary form. There is a beginning section, a middle, and an end which is a sort of repeat of the beginning. First main themes are exposed, then in the middle developed or elaborated, and finally everything is recapitulated. Harmonically, in middle areas we shift to different tonal regions to provide contrast before bringing everything to the home region (called tonic) in the end.
Let's go through the piece.
Score: http://petrucci.mus.auth.gr/imglnks/usimg/b/b8/IMSLP20286-PMLP18979-Mendelssohn_-_090_-_Symphony_n.4_A__score_.pdf
Youtube:
Right away, we open with the principal theme, played by the violins. (pg. 1)
I've circled the first motif, (a), and call the whole theme A. The rhythm of (b) is important as well. This first theme is in the key of A, the main key. Motif (a) appears a lot, and I won't mention them all, but you can listen for it.
![[image loading]](http://i.imgur.com/wQk2g.jpg)
On page 4, note the alternating staccato notes, for now. Not just notes and rhythm, but texture can be used as a sort of motif as well. (0:56)
![[image loading]](http://i.imgur.com/ZRhQf.gif)
On page 6, the second theme (B) is played by the clarinets and bassoons. (1:32)
![[image loading]](http://i.imgur.com/VWirX.gif)
Notice that the rhythm is taken from (b) of the (A) theme, and the intervals are similar to the second section of that theme too. Why do I call this a new theme and not a variation, or what makes a theme more than just a melody? The answer is the way it is used. A theme is elaborated and used to germinate new material. Here, (B) is in the key of E (the fifth of home key of A), and functions in this movement as the second theme introduced in the first section, a feature of the sonata-allegro form. Changing keys creates contrast and tension. Before rehearsal marking B on page 9, theme A reappears, now in E major! (2:24)
The whole first section is then repeated, and the middle section starts afterwards with the 2nd ending. (NOTA BENE, this youtube video linked above doesn't repeat.) (pg. 11) We modulate from E major briefly to a minor and then d minor. The 2nd violins introduce a new theme. It starts in d minor, but we don't stay there long. Middle sections are marked by frequent key changes.
Theme C, note the relationship to the alternating staccato notes above. "Insignificant" details often become motifs or themes. (2:54)
![[image loading]](http://i.imgur.com/yJkzH.gif)
So at the end of page 13, we end up in B minor with the strings tossing around theme (C), when the winds suddenly interject with theme (A), in B major (3:32), and they fight for awhile, with the winds playing (A) and strings (C), now in major. Then the (A) theme wins, momentarily. We climax after a climb back to B major, but not resolving to the full (A) theme in E major as might be expected (V-I cadence), but back to the (C) theme in e minor. Pg. 15: (3:57)
![[image loading]](http://i.imgur.com/jdOYw.gif)
Afterwards we calm down with riffs on motif (a), before leading into the third section, the recapitulation. This is at rehearsal marking D on page 18. We've returned to the main theme, in the home key of A major. (5:03)
On page 20, we arrive at the second theme (B), but now it is in A major. It was first introduced in E major, to create contrast. Now we are resolving everything. (5:34)
Similar on page 22, theme (C) comes out to play, in A minor. (6:21) At the end of page 23, we switch to A major, with the strings playing the main theme, and the winds finishing (C). (6:45)
Finally, after a transition, the three themes join together in the coda.
![[image loading]](http://i.imgur.com/N7Nty.gif)
![[image loading]](http://i.imgur.com/HIqVa.gif)
Hope that wasn't too hard to follow. I love this movement and I urge you to seek out other recordings if you liked it.
. Although I like your format.
