Something extraordinary arrived at the Terrace Theater last night -- from Nigeria by way of Chicago.

The something is Wole Soyinka's "Death and the King's Horseman," a physically spectacular, intellectually stimulating, stylistically eccentric play that mixes motifs from an assortment of cultures and centuries. Far less ambitious pieces of theatrical cargo have suffered terrible damage crossing the Atlantic, but this elaborate package seems to have been handled with care all the way.

Based on real events in post-war Nigaeria (post-Second-World-War, that is), "Death and the King's Horseman" opens amid verse, music and spectacle as Elesin Oba, the late king's chief horseman, prepares to commit ritual suicide so he can join his king in heaven. On his last day among the living, Elesin spies a beautiful girl and asks the women of the marketplace -- who serve as an ongoing chorus -- to send her to him.

But the girl is engaged, Elesin is curtly informed. Would he "blight the happiness of others for a moment's pleasure?"

"Who speaks of pleasure?" he asks. He wants to make his departure free of all regrets -- to "travel light" into the beyond, he says. And he would like to leave the seed of a child to "take root in the earth of my choice." To this the elders yield, guided by Iyaloja, the "mother of the marketplace" whose own son was to have married the girl Elesin has selected.

Then the action shifts to the colonial district officer's bungalow, and the style turns suddenly brittle and comic. The district officer, archly named "Simon Pilkings," ridicules tribal ritual while making his own elaborate plans to attend to costume ball at the local European Club.

Learning of Elesin's suicidal intent, Pilkings arranges to have him locked up, and heads off to the ball (where the guest of honor is a visiting English prince, on tour in the colonies). Elesin's English-educated son, a protege of the Pilkings, also shows up, having returned to Nigeria to be with his father at his death.

From here, the play acquires the rolling momentum of classical tragedy; but while the conclusion is true to the grim course of preceding events, it has a 20th-century twist.

Soyinka is fascinated with the "irrationality" in all cultures -- the need for it when addressing issues of life, death and birth, and the pretense of earth-shaking importance to which we give clashes between one culture's irrational tenents and another's.

The Goodman Theatre of Chicago fought for two years to bring this play to the United States, and they wisely brought the author along to direct it. So with due allowance for the adjustment problems of American actors learning African attitudes and inflections, we are probably entitled to assume that the Chicago/Washington-version of the play bears at least a strong resemblance to the work that premiered at Nigeria's University of Ife in 1976.

However authentic, it is a compelling production The scenery works inventive and colorful variations on a slate-gray foundation. The costumes are a feast for the eye. And the cast -- while the accents may waver now and again -- performs with an air of authority throughout.

As Elesin, Norman Matlock has some difficulty with the play's tragic resolution, but otherwise he makes impressive use of his rich voice and athletic grace.

As Iyaloja, Celestine Heard also possesses an awesome voice and bearing. And as Pilkings, Alan Coates manages to make a convincing whole of the contrary sides of this initially absurd but later more complicated character.

To an American viewer, Soyinka's play has confusing passages, and the imagery gets a bit crowded at times. How vauable is for example, to compare a son's pity for his dishonored father with the pity of a thoroughbred horse "for the turf he strikes with his foot?" An Sayinka hits some of his points too squarely, reducing the character of Elesin's son to little more than author's mouthpiece.

The most serious problem of all is the final scene, where the impact of classical tragedy is usually best measured. As rendered at the Terrace, "Death and the King's Horseman" ends with all the right tragic rhythms and, strangely, a good deal less than expected emotional force.

But the task Soyinka set for himself was so ambitious that even partial fulfillment makes exciting theater.