Perhaps the most praised element of the production was the score by John Barry, then most famous for his "James Bond" scores. In the new millennium, it was still regarded as one of his best scores. In a project to prepare a special CD release of the soundtrack, it was discovered that the complete original session recordings were either lost or destroyed.

The Captain changes sides at least once during the war. To have participated in the sack of Magdeburg, he must've fought with the Imperialists. At the end of this movie, he joins the army fighting against the Imperialists. Such fickle behavior was far from uncommon amongst mercenaries of the period.

Apparently, prior to this movie being made, the only time a movie had depicted the Thirty Years War was Queen Christina (1933).

The Captain (Sir Michael Caine) refers to the sack of Magdeburg having occurred twelve years previously. The sack took place in 1631, so the events of this movie occur in 1643 to 1644.

American Broadcasting Company's feature production arm, ABC Pictures, intended this to be their break-out prestige production. With their already existing distribution deal with the Cinerama Releasing Corporation, they decided to shoot this movie in the expensive Todd-AO process. It opened as a roadshow presentation in Cinerama venues. The returns were disappointing. The roadshow release was expanded to venues that could show 70mm "flat" prints. With more disappointing returns, this movie quickly went into general release with 35mm anamorphic prints. This movie became a phenomenal box-office disaster. It reportedly grossed less than twenty percent of its production cost. With millions of dollars in losses, ABC Pictures ceased production in 1972.

Sir Michael Caine's character is only ever called "The Captain", and is never known by any personal name.

This movie, which was shown in Cinerama venues, was the last movie to use the Todd-AO system for principal photography, until Baraka (1992).

This movie was written, produced, and directed by a novelist James Clavell, but the movie was not a filmed adaptation of one of Clavell's own novels. It was a movie adapation of a novel by J.B. Pick.

The opening prologue states: "The Thirty Years War began in 1618. It started as a religious war - Catholics against Protestants. But in their relentless pursuit of power, princes of both faiths changed sides as it suited them and in the name of religion butchered Europe."

Martin Miller was booked to appear in this, but while filming, he died from a heart attack, according to Brian Blessed. Edward Underdown took over the part Miller was to play.

Average Shot Length = ~5.3 seconds. Median Shot Length = ~5.0 seconds.

This movie was released twelve years after its source novel of the same name was published.

Final theatrical movie produced or directed by novelist and screenwriter James Clavell.

George MacDonald Fraser, a screenwriter of historical and adventure stories, who, during the 1970s, was hired to write an adapted screenplay of James Clavell's Tai-Pan (1986) novel, which was not produced, once said of this movie: "The plot left me bewildered - in fact the whole bloody business is probably an excellent microcosm of the Thirty Years' War, with no clear picture of what is happening, and half the cast ending up dead to no purpose. To that extent, it must be rated a successful film . . . As a drama, The Last Valley (1971) is not remarkable; as a reminder of what happened in Central Europe, 1618 to 1648, and shaped the future of Germany, it reads an interesting lesson . . . Michael Caine . . . gives one of his best performances as the hard-bitten mercenary Captain, nicely complemented by Omar Sharif, as the personification of reason".

Omar Sharif and Sir Michael Caine appeared in Ashanti (1979).

The time of the historical battle in which this movie is set is the "Thirty Years' War", which occurred between 1618 and 1648.

Edward Underdown (Gnarled Peasant) was dubbed.

Frazer Hines (Corg) spent eighteen weeks filming his role.

J.B. Pick's original novel has been published under a slightly different title in some editions, as "A Fat Valley".

Michael Caine starred along side Michael Gothard in the TV series Jack The Ripper and with Nigel Davenport in Without a clue. Both of which were released in 1988.

Finnish censorship visa # 76668 delivered on 5-5-1971.