The Prince by Niccolò di Bernardo dei Machiavelli

A famous writer by the name of Niccolò di Bernardo dei Machiavelli.
Famous for the book: The Prince

It explains the qualities the ideal prince should possess, modeled after Cesare Borgia. These are still cited in modern texts on leadership. The traits of an effective political leader are presented as:
1.) A willingness to imitate the behavior of great men, e.g. those of Ancient Rome in particular, the book being written in the Renaissance.
2.) The ability to illustrate how government is necessary to the well-being of the populace, e.g. perhaps by demonstrating the consequences of yielding to mob rule by temporarily relaxing one's grip.
3.) A dedication to the art of war — if only for the state's actual survival.
4.) An understanding that apparent cruelties and vice may be essential to maintaining stability and power.
4.) Prudence with respect to disbursement of one's own wealth.
5.) Making efforts to appear religious to sway the "vulgar." Machiavelli extols King Ferdinand of Spain for using the cloak of religion to invade Italy numerous times — he praises the tactic yet hates the invasion of Italy by other monarchs.
6.) The wisdom to seek advice and counsel only when it is needed.