"An die ferne Geliebte" by Beethoven can be seen as the first real song cycle by a great composer in the sense that it is a number of songs by voice and piano that are clearly related with each other. "An die ferne Geliebte" has a clear coherence. First, the six songs of the cycle flow into each other. Second, the tonal structure is very clear: Es-G/C/G-C/As-As-C-Es. Also the poetic structure is clear: Trochee, Anapest, Trochee, Trochee, Anapest, Trochee. The theme of the first song is re-exposed in the last song.
The song cycle is composed in 1816, where the "ferne Geliebte" is probably Antonie Brentano, spouse from Beethovens' friend Franz Brentano (Van der Zanden, 1994: p. 87). This love for a married woman started probably in 1811, but it had no future and they broke up. In 1816 Beethoven told a friend about his only great love that he couldn't forget about. Probably in 1812 he wrote a letter that has been found after Beethoven's death to "die unsterbliche Geliebte", that is probably the same person. It has to be mentioned that a lot of other hypotheses have been formulated about the identity of the "unsterbliche" and "ferne" Geliebte.
As most of Beethoven's compositions, a lot of sketches have been made before the final version was published. Before the publication the title of the cycle was "an die entfernte Geliebte". The cycle of poems have been written by A. Jeitteles, a medical student and not a very high quality poet. Probably Beethoven has asked him to write the poem. And probably the last line of the first song that is repeated in the sixth song has been added/rewritten by Beethoven to create the opportunity for a re-exposure of the theme of the first song.
The song cycle has been a great inspiration for later writers of song cycles, where motives have been used also in instrumental pieces of many composers (especially Schumann).