Questions about the article "the". Thanks.

Dear all,

I have two questions about the article “the”. Could you help me with the,? Thank you very much.

I want to ask why we have to put "the" in bold before enighteen century and beginning in the sentence 1and 2. Are there any grammar rules to explain my questions?

1. Until the eighteenth century, only Aborigines lived in Australia.

2. The expedition had problems from the beginning.

My second question is that why we do not put "the" before camels, horses amd supplies in the following sentences.

3. The original sentence: Burke was chosen to lead an expedition across Australia from south to north. He took with William John Wills and eleven other men, camels, horses, and enough supplies for a year and a half.

The revised one: Burke was chosen to lead an expedition across Australia from south to north. He took with William John Wills and eleven other men, the camels, the horses, and the enough supplies for a year and a half.

If I put "the" before these words, it will convey the different meanings. My explanation is that camels and horses without the means that Burke took more than one camels. They could be 10 camels or 100 camels. However, if an author wrote Burke took the camels, this means that Burke took all camels he has and the author knew how many camels Burke has and he took all of them.

Thanks again.