It is always a useful opening to say what one is not going to talk about, so I shall start by saying that I am not going to talk about the influence of Seneca on Elizabethan tragedy. That is a topic which during the last couple of generations has probably suffered from over-exposure, and the pendulum has now swung from excessive claims for Senecan influence (ghosts, blood-and-thunder, the whole apparatus of the ‘Revenge’ play, and so forth) to the other extreme of allowing perhaps too little of Seneca in sixteenth-century tragedy – not even as much as the rhetorical features for which it seems to me he is clearly responsible. So perhaps we can give this topic a rest – a lot of books and articles have been written about it anyway. What I want to do is to explore some sixteenth-century critical attitudes to Seneca – mainly his tragedies, but his prose works will come into it as well. We shall see, I think, some interesting preoccupations which a wide-ranging and intelligent number of scholars had in what they said about Seneca – in particular, his style – and this will lead to a consideration of Polonius' well-known remark to the players in Hamlet (II. 2. 392 ff.): ‘Seneca cannot be too heavy nor Plautus too light’, and the question what precisely he meant by ‘heavy’. In doing this we shall not simply be burrowing into a rather dusty and recherché corner of literary criticism, but I think we shall be able to throw some light on wider aspects of Renaissance poetic and dramatic theory, which I am certainly not competent to discuss in detail; but I may stimulate somebody else to go further than I have done.