<Li> (1415--1433) João I </Li> <Li> (1908--10) Manuel II </Li> <Tr> <Td_colspan="2"> Presidents </Td> <Td> <Ul> <Li> (1911--15) Manuel de Arriaga </Li> <Li> (1996--99) Jorge Sampaio </Li> </Ul> </Td> </Tr> <Ul> <Li> (1911--15) Manuel de Arriaga </Li> <Li> (1996--99) Jorge Sampaio </Li> </Ul>

Describe how the portugese gained dominance of the spice trade