Niccolo Machiavelli (1469-1527) most famous work, The Prince, was his observations of how people in power operate. The fact that the work continues to be read and argued over suggests that his observations unfortunately were accurate. One of the precepts in The Prince is the "compartmentalization" of people -- in other words, telling one person or group one thing, and another group or person something else to achieve some end, even if what was stated later contradicts what was stated earlier. Politicians do this all the time, promising tax cuts when speaking to the wealthy and additional government aid when speaking to the poor.
In Othello, Iago makes a speech where he shows to the audience his intent -- to enmesh all the characters to advance his own cause -- telling Othello that Desdemona is advocating for Cassio because she is his secret lover, when in fact, she is attempting to rectify his demotion in rank and repair the rift between Cassio and Othello, which was also manipulated and caused by Iago!