It was during the period of his connection with Madame du Châtelet, that is in the active literary years between his return from England and his removal to Berlin, that Voltaire’s dramatic talent was most productive.[105] He is usually considered to hold the same place relatively to Corneille and Racine that Euripides held relatively to Æschylus and Sophocles. It is not easy to see what is the exact point of analogy on which the critics agree, beyond the corresponding place in the order of chronological succession, and such parallels are not really very full of instruction. If we are to draw any parallel at all, it must be between the Greek and Racine. The differences between Euripides and his predecessors are not those between Voltaire and his predecessors. There may be one common peculiarity. Each made the drama an instrument for the expression not merely of passion, but of speculative and philosophical matter, and this in each case of a sceptical kind in reference to the accepted traditions of the time. But apart from the vast superiority of the Greek in depth and passion and dramatic invention, in Voltaire this philosophising is very much more indirect, insinuatory, and furtive, than in the marked sententiousness of Euripides. There are critics, indeed, who insist that all Voltaire’s poetic work is a series of pamphlets in disguise, and that he ought to be classified, in that jargon which makes an uncouth compound pass muster for a new critical nicety, as a tendency-poet.[106]