An intense desire to be independent and free of foreign rule is

An intense desire to be independent and free of foreign rule is nationalism.

Explanation:

Nationalism is the concept that guides one people to determine that they form one nation with one singular and consistent identity and it is this identity identified within a geographic constraint that the country must exist as a self determining sovereign power.

The nationalists when under the rule of foreign powers are often thus with intense desire to be independent and free of foreign rule as only then can the result of this nationalism can be seen.

An intense desire to be independent and free of foreign rule is  "decolonization".

Explanation:

Decolonization is specifically the ultimate downfall of colonialism, which may be the mechanism by which a country develops and retains its control over overseas territories. While nationalism is not specific, it can be very general among citizens.

Decolonization refers in specific to the dismantling of the colonial empires founded before World War I worldwide during the second half of the 20th century. It may entails by pro-independence movements either peaceful resistance or wars of national liberation. This may be intra-national or include foreign forces working personally or via international institutions such as the United Nations.

the enslaved people onboard suffered from illness with some frequency

la segunda guerra mundial comenzó el 1 de septiembre de 1939 y terminó el 2 de septiembre de 1945. ¡espero que esto ayude!