The terrorists who seized a train and a school yesterday are part of a community of South Moluccans, now numbering 40,000, that has lived in the Netherlands since the Moluccan Islands were absorbed into Indonesia in 1950.

In recent years, South Moluccans have claimed responsibility for a series of violent, sometimes thwarted terrorist acts in their campaign to win independence for their homeland.

A policeman was killed in 1973 when South Moluccans seized the Indonesian embassy in The Hague during a visit by Indonesian President Suharto. In 1974, South Molucans stormed and damaged the Hague Peace Palace.

Plots to kidnap ambassadors, government officials and Dutch Queen Juliana were uncovered by security officials.

In their most spectacular attack, in December 1975 South Moluccan terrorists simultaneously hijacked a train in the north of the Netherlands and occupied the Indonesian consulate in Amsterdam. The two sieges lasted almost three weeks, and four persons died. The terrorists were sentences to terms ranging from six to 14 years in prison.

The Moluccans, once known as the Spice Islands, are a group of about 150 islands in eastern Indonesia. Their population of 995,000 is less than 1 per cent of Indonesia's total population, 121 million. Their land area is 32, 307 square miles, about the size of Maine.

The islands were discovered by Portugal in 1512 and captured in the early 1600s by the Dutch, who brought in African slaves and developed the spice trade.

When Indonesia won independence from the Netherlands in 1949, residents of the Moluccans, decendants of the East Indians and the African slaves, sought separate independence and, after an uprising 12,000 were forcibly sent to the Netherlands.