Mr. Mandela entered the chamber with his arm around his predecessor, F. W. de Klerk, and settled into the brown leather seat from which Mr. de Klerk led the repeal of apartheid during the last four years.

Mr. de Klerk, still president for a day, moved across the aisle to the place from which the pro-apartheid opposition used to harangue him as a traitor to his race. In the new order, he is one of two vice presidents.

Behind them the assembly fanned out in a florid display of races and costumes, white men in suits outnumbered by black women in the bright hats that are the feminine custom of the house. The Parliament is roughly a mirror of the public, which is about 75 percent black, 15 percent white, and 10 percent Indian and mixed-race.

The spectacle today shattered not only the South African tradition of minority dominion but also the stereotype of liberation parliaments, for here the former prisoners were sworn in alongside their former jailers, returned exiles sat across from recycled racists, and the descendants of the system joined its victims and the next of kin. Bitter Foes Embrace

All are now $55,000-a-year incumbents who will address each other as "honorable member" in the same spirit with which Mr. Mandela bounded from his place today to embrace his Zulu nationalist rival, Chief Mangosuthu G. Buthelezi, and to pump the hand of Gen. Constandt Viljoen, parliamentary leader of the nine-member white separatist delegation.

The new legislators came forward in flights of 10 to be sworn in, each lineup containing several novels' worth of pain endured and history upended.

In the first batch, together with Mr. Mandela, stood his estranged wife Winnie, the militant champion of the dispossessed and convicted kidnapper. Mr. Mandela ignored her, staring away as they pledged their devotion to the new South Africa, and ignored her again later when she sat briefly beside him to nominate the deputy Speaker.