What is columbus primary purpose in his letter?

In 1517, the spanish friar bartolomé de las casas, disturbed by the suffering which spanish conquistadores had wrought on the native populations of america, became an important advocate of

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.

Aclaim about history is most likely not valid if it has which of these characteristics?