Hamlet's character is the expression of overwhelming grief to seething rage. Sometimes there is real madness and sometimes it is feigned.The most important themes are revenge, treachery, incest, and moral corruption.The exact date of its writing is not known, but the three different early version of "Hamlet" have survived. These three versions are First, Second, and Third Quarto. Each of these versions has the lines and scenes which are missing from the others.The character of Hamlet is based on the legend of Amleth, which was preserved by the nineteenth century historian Saxo Grammaticus in his Gesta Danorum. The story was retold later in the sixteenth century by Francois de Belleforest, a scholar. An earlier play which was perhaps written during the Elizabethan era was titled "Ur-Hamlet."