Complex sentence: Greek orators spoke on their own behalf rather than on behalf of representatives of either a client or a constituency, and so any citizen who wished to succeed in court, in politics, or in social life had to learn techniques of public speaking.
Split into simpler sentences: Greek orators spoke on their own behalf rather than on behalf of representatives of either a client or a constituency. So, any citizen who wished to succeed in court, in politics, or in social life had to learn techniques of public speaking.