Before we go to the movies next Saturday night at Wolf Trap, it might be a good idea to look at exactly what we mean by "Terrible." As in "Ivan the Terrible," the film by Sergei Eisenstein, from which scenes will be shown while the National Symphony Orchestra and conductor Michael Lankester play Sergei Prokofiev's soundtrack music.

The Russian word grozny (as in "Ivan Grozny") means "terrible" in our modern American sense of "extremely not nice," and that certainly applies to Ivan IV (1530-1584), the bloodiest ruler in Russian history before Joseph Stalin, a man who killed his son in a fit of anger and who went through more wives than his approximate contemporary Henry VIII of England. But grozny also means "awe-inspiring" -- that which provokes reverence or terror. This meaning of the word also applies to Ivan, the first man who brought the vast Russian territory under a single, strong rule and the first who publicly claimed or deserved the title "Czar of Russia."

The "awesome" dimension of grozny was foremost in Eisenstein's mind when he made his film. It was produced, after all, under the all-seeing gaze of Stalin, who forbade release of the second part of "Ivan Grozny" because he thought it did not make the old despot look good enough.

Ivan became the titular ruler of Muscovy when he was only 3 and actually began ruling at 14. He wanted to wipe out the boyars, the hereditary nobles whose power and rivalry kept Russia disunited and weak, and he nearly succeeded. In the benign period of his reign, roughly from 1550 to 1560, he greatly extended the territory under Muscovite rule; his conquest of Kazan (one of the big scenes in the movie) was a turning point in Russian history. Near the end of his reign, he expanded his kingdom to Siberia and throughout he promoted the rise of the middle class and the development of the arts and commerce.

But even at his best, there was a streak of sadism in Ivan's character, a contempt for human life and a vein of paranoia. These elements came out strongly in the 1560s after he had lost the best of his advisers, experienced attempted assassination and lost his wife (poisoned by boyars). His critics began to die violently and he destroyed whole cities. Good or bad, grozny in all senses of the word, Ivan inspired Prokofiev to compose some of his finest music -- music that deserves to be heard more often than the film is played and with better sound.

It was essentially celebratory music, written in wartime while Russia was being torn apart and recalling the man who first made Russia strong and united. "Even without Stalin on the horizon," says Lankester, who has reworked the music twice, "I found it impossible to work in any of the numerous brutalities Ivan was responsible for ... to read off an account of his atrocities in the middle of Prokofiev's music... . What intrigues me is the idea of someone writing a paean of praise to this man four centuries after his atrocities; I can't help wondering whether someone will write a paean to Adolf Hitler four centuries from now."

Various efforts have been made to give the music a new life apart from the film. An oratorio, arranged by Abram Stasevich, was first performed in Moscow at the celebration of the 70th anniversary of Prokofiev's birth. It has been recorded and was reworked into the ballet score that was brought to Wolf Trap last week by the Bolshoi Ballet. Last year, at the Kennedy Center, the National Symphony performed Lankester's first arrangement of the soundtrack music, using a narrator. His second arrangement, using the actual film, is the one he will conduct Saturday night. He will also conduct "Alexander Nevsky," with the film, on Friday night. It was the success of "Nevsky," which had a capacity audience at Wolf Trap last year with the NSO playing the soundtrack music, that inspired producer John Goberman (best-known for his work as producer of "Live from Lincoln Center" on PBS) and Lankester to expand the project with "Ivan."

The two-day double feature was a huge success in Italy, where it had its first performances earlier this month, Goberman reported on his return from performances at Pompeii and Agrigento. "In Pompeii, where this version of 'Ivan' had its world premiere, there were 10 minutes of applause -- a screaming ovation," Goberman says. "You hear the music in a way that makes its quality clear ... most people don't know 'Ivan the Terrible.' When you see it with the images it was written for, you realize what a great piece of music it is."

Unlike his production of "Alexander Nevsky," which could be called a movie with orchestra, Goberman says that "Ivan" is "much more of a concert with film; there are some sections where we let the orchestra just play without a picture but, curiously, most of the great music in the score corresponds to the great scenes in the movie."

There is one odd technical point about "Ivan," which was shot from 1942 to 1945, Goberman notes: "The film begins in black and white, but the end of it is shot in color. This is because the Russians had just captured the Agfa film works in Germany, and their color capability was suddenly enormously increased."

"Ivan" is quite a different film from "Nevsky," even making allowances for the different characters of the two men (Alexander Nevsky is recognized as a saint by the Russian Orthodox Church). "Nevsky" was Eisenstein's first epic collaboration with Prokofiev and the first film he had been allowed to make after seven years in a Stalinist limbo. "It feels like the work of a young man -- fresh and vibrant -- and of course it is fairly short," according to Lankester. " 'Ivan' is huge and sprawling -- it would take forever if we did the whole thing -- and it has a darker subject. I think it is as great a film as 'Nevsky,' but it is totally different, full of Machiavellian characters and sinister intrigues."

These two films fall in with a trend that has been growing more noticeable in the last few years: The National Symphony Orchestra seems to be spending more and more of its summer programs in the exploration of Russian history. The longest standing and most popular part of this project is the annual "1812" overture (about Napoleon's invasion of Russia), which is always done twice at Wolf Trap and was performed last July 4 on the Capitol lawn. Last year, there was also a special concert performance of Mussorgsky's opera "Boris Godunov," which looks at what happened after Ivan the Terrible's death and which is now available on Erato Records in an NSO studio recording. "Alexander Nevsky" is about a medieval attempt by the Teutonic knights to invade Russia, and "Ivan the Terrible" is about (among other things) the forging of a united Russian nation.

Goberman would like to see this trend continued and extended, but has no definite plans about how. "We're looking for the next 'Ivan the Terrible,' " he says. "There are 26 Shostakovich soundtracks, but we haven't found the right one yet."

How about Prokofiev's opera "War and Peace"? It is a composition at least as epic as "Nevsky" or "Ivan," and hasn't been done at Wolf Trap in years.