Alexander the Great

After he won his great conquests and victories, Alexander the great became... not so great. He fell into vanity and surrounded himself with fawning courtiers, 360 concubines, and wealth. Generally, he just lived in luxury and got everything he wanted. Over time, a rumor began getting spread around that someone wanted to stick a dagger in between Alexander's ribs. He naturally began to suspect the one person that persistently advised to end his luxurious and corrupted life. He had this person's son tortured, and then when his son in horror "confessed", had the son and the father exected.