The song also exists in-universe: it's the song sung to the Doctor by the Ood. Should we split this? Make it an in-universe page with a plentiful BTS section? This needs discussing.
"Vale Decem" was the song which incidentally scored the final moments of the Tenth Doctor's life in The End of Time, part two. It was written by Murray Gold and principally sung by Mark Chambers, with choral by the Crouch End Festival Chorus and orchestration by Ben Foster and the BBC National Orchestra of Wales. In addition to its use in the episode, it was made available for public performance on at least two other occasions. It was performed live at the 2010 Doctor Who at the Proms and released to home audio on Doctor Who - Series 4 - The Specials.
On the soundtrack, the piece is broken into two sections. One, called "Vale Decem" — which, in the episode, is the bit until the Tenth Doctor's last words, "I don't want to go" — and the other, "Vale", which is the primarily orchestral and non-verbal choral "response" played during the regeneration itself. The latter incorporates the melody of "The Doctor's Theme". However, the division is largely artificial, as the two share essentially the same melody. Indeed, the distinction was not made during the live Proms performance, where both parts were played under the title, "Vale Decem".
"Vale" was first introduced at the end of The Waters of Mars, foreshadowing the Tenth Doctor's ultimate demise.
Within the narrative of The End of Time, this track is foreshadowed by "We Shall Fare Well", Gold's "faux Christmas carol" sung by the boys' choir at the top of part one. That piece gives much the same sentiment of this song, but in English.
|Vale Decem||Farewell Ten|
Behind the scenes
- Murray Gold has stated that the Ood's songs are heard in Latin because the TARDIS translated them from "Classical Ood" to the language closest in style and spirit. 
- Because the melody of "The Doctor's Theme" is incorporated into "Vale" (which is heard by the Tenth Doctor, this means the melody (but not the song itself) exists in the DWU.