Though we already have Cicero's letters arranged for us in a chronological sequence which may be held to be fairly correct for biographical purposes, still there is much doubt remaining as to the exact periods at which many of them were written. Abeken, the German biographer, says that this year, B.C. 55, produced twelve letters. In the French edition of Cicero's works published by Panckoucke thirty-five are allotted to it. Mr. Watson, in his selected letters, has not taken one from the year in question. Mr. Tyrrell, who has been my Mentor hitherto in regard to the correspondence, has not, unfortunately, published the result of his labors beyond the year 53 B.C. at the time of my present writing. Some of those who have dealt with Cicero's life and works, and have illustrated them by his letters, have added something to the existing confusion by assuming an accuracy of knowledge in this respect which has not existed. We have no right to quarrel with them for having done so; certainly not with Middleton, as in his time such accuracy was less valued by readers than it is now; and we have the advantage of much light which, though still imperfect, is very bright in comparison with that enjoyed by him. A study of the letters, however, in the sequence now given to them affords an accurate picture of Cicero's mind during the years between the period of his return from exile B.C. 57 and Milo's trial B.C. 52, although the reader may occasionally be misled as to the date of this or the other letter. With the dates of his speeches, at any rate with the year in which they were made, we are better acquainted. They are of course much fewer in number, and are easily traced by the known historical circumstances of the time. B.C. 55, he made that attack upon his old enemy, the late Consul Piso, which is perhaps the most egregious piece of abuse extant in any language. Even of this we do not know the precise date, but we may be sure that it was spoken early in the year, because Cicero alludes in it to Pompey's great games which were in preparation, and which were exhibited when Pompey's new theatre was opened in May.[28] Plutarch tells us that they did not take place till the beginning of the following year.[29] Piso on his return from Macedonia attacked Cicero in the Senate in answer to all the hard things that had already been said of him, and Cicero, as Middleton says, "made a reply to him on the spot in an invective speech, the severest, perhaps, that ever was spoken by any man, on the person, the parts, the whole life and conduct of Piso, which as long as the Roman name subsists must deliver down a most detestable character of him to all posterity."