[...] This time I have left your friendly letter rather long unanswered. I am often so overwhelmed with correspondence that I am forced to put off writing a letter for which I need to be in the vein. I am sorry that you have taken my report of the rumour about your "dread" of Rienzi, amiss. You very rightly opine that it was mere green-room gossip, but I believed the best thing to do was to tell you frankly of the matter. I hope it may have the effect of bringing us to a really good understanding on this occasion so that we can achieve an original piece of work. I had indeed given up this Rienzi altogether. Through Tichatschek's huge vocal skill [...] it had got the name of being his speciality which he only could represent successfully. Now that I have come across you, my interest in the whole thing has revived and I am glad of the opportunity of going over the ground with you as well as can be done by letter.
In studying the main trend of this character the chief thing, then, as I have already intimated, is to have a firm grasp of the following.
Nothing influenced Rienzi's youth more strongly than the brutal murder of his small brother by the soldiery of the nobles, against whom he could get no justice. Feeling at first this longing for vengeance which he was unable to satisfy and brooding over it, he recognised the grounds of the evil in the universal misery of his time and more especially of his own country. To get at the cause he studied the history of his country, up to its source in Roman antiquity, plunged with enthusiasm into contemplation of the sublimity and greatness of ancient Rome, and then, turning to the present, became conscious of monstrous corruption. Ceasing to brood on his unsatisfied vengeance he looks upon a world sunk in degradation and determines to set it free. In this way the original "vendetta" motive is purified, becomes inspired, exalted patriotism, which thrusts back all memory of personal injury, and gives him the miraculous power which, for a season, he exercises over his people. Rienzi's exact opposite is presented in Adriano. In him the foundation is based on the enthusiasm which Rienzi knows so well how to inspire in the lad on the ground of his love for Irene. But instead of maintaining the enthusiasm which in time lifts Rienzi above all natural and personal attachments, Adriano sinks down to the position whence Rienzi set out. "Blood" comes between the two and Adriano cannot rise above the emotions of the vendetta. He remains tangled in mere family ties (whereas Rienzi sees nothing but the state as a whole). Adriano, however, craves for revenge, scarcely controlled by his love, and perishes powerless and witless, while Rienzi, raising the battle hymn, allows himself to be crushed amidst the ruins of the Capitol by an ungrateful and misguided people.
Apart from picturesque detail this is the main trend of Rienzi's characterisation, and must be strongly emphasised by the actor. [...]
I do not know whether I have made myself clear, but I have grown warm over this youthful subject of mine which I only rightly understand now. I hope I may have imparted some of my warmth to you, for thus only will you find the true path of sincerity and profound understanding, things I could never ask of the good, excellent Tichatschek—I do not doubt your success. You must popularise this opera. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 389