What three spices were only available to Europeans in the Middle Ages from the "Spice Islands" of the Moluccas (Indonesia)?
Cloves, nutmeg and mace grew only on a few small volcanic islands of the Moluccas; now the Maluku Province, which is part of the nation of Indonesia. Archaeology has shown that more than 3000 years ago cloves from the Moluccas were traded to Persia. The Romans were able to buy spices and other luxuries from the remote east of Indonesia.
Because spices were sourced from the other side of the world they were very expensive in Medieval Europe. Their delivery was largely in the hands of the Moslem world with which Catholic Europe was often at war. Spices attained huge luxury value as emblems of conspicuous consumption.
It was the Portuguese who developed navigation and map-making whilst making voyages of exploration which culminated in Vasco da Gama reaching India in 1497. The sea route to Asia around the Cape of Good Hope allowed the Portuguese to bring spices direct from the markets of Southeast Asia to Europe. It was a dangerous but hugely profitable trade.