Petrarch, de Vita Solitaria 2.12:
I see that Cicero is the only one of this type who could not bear solitude with equanimity. I think that it occurred not because he hated his solitude itself as much as because he hated its cause – that is, the death of law and justice – which the tenor of his complaints indicates. It happened that that except in philosophy the greatest orator (and he did not himself hide this fact), seeking glory especially in this part of his studies, certainly never found it except in the crowds and in the midst of all the people. And so, as he was about to defend the king Deiotarus in front of Julius Caesar, he complains that he is conducting the case within the walls of a house and not in sight of the Roman people.
It is unique and particular to orators that, in respect to the magnitude of their genius they are delighted by great cities and the density of the population, they detest solitude, and they are both opposed to and hate the silence of judges. Therefore, as lesser people did with their own cities, thus Cicero longed for the city of Rome, not just as his fatherland, the more dear to him as he had spent so much care and labor in conserving and ornamenting it, but as a fatherland equal to his genius.
Here I might use Seneca as a witness, who was not afraid to say that only Cicero’s voice was truly alive, although that is attributed by an error of public speech to many; he was also not afraid to affirm that only Cicero’s genius was equal to the power of the Roman people, if – and this is truer than any witness – the most parent evidence of the case did not show that just as the crown went of power and glory went to the Roman people, so the crown of genius and eloquence went to Cicero.
But what that solitude granted to Cicero, however unwilling, is well known: he transformed himself from the greatest orator into a great philosopher, from which fact there is no studious person who does not know how much accrued to Latin studies.

Unum hoc in genere Ciceronem video non sat equo animo ferre solitudinem. Quod contigisse arbitror, non tam ideo quia rem ipsam, quam quia rei causam odisset, legum ac iustitie interitum, quod ipse querelarum suarum tenor indicat. Accedit quod preter philosophiam, oratorum maximus, quodque nec ipse dissimulat, de hac studiorum parte precipue gloriam querens, nusquam profecto illam nisi in turbis et magno in populo videbat. Itaque coram Iulio Cesare, Deiotarum regem defensurus, queritur quod intra domesticos parietes et non coram populo Romano causam illam agat.
Est illud oratoribus singulare et proprium ut pro magnitudine ingenii magnis urbibus ac populorum frequentia delectentur, solitudines execrentur, iudiciorumque silentium adversentur atque oderint. Ut ergo minores alii suam quisque, sic Cicero urbem Romam, non solum ut suam patriam, eo sibi cariorem quo in eam conservandam atque ornandam cure plus ac laboris impenderat, sed ut patriam ingenio suo parem exoptabat.
In quo quidem teste Seneca uterer, qui solam Ciceronis vocem vere vivam dicere, quanquam id errore sermonis publici multis attribuatur, solum Ciceronis ingenium Romani populi imperio par affirmare non timuit, nisi, quolibet teste veracior, evidentissima rerum fides ostenderet, fuisse ut populo Romano imperii et glorie sic Ciceroni ingenii et eloquentie monarchiam. Ceterum quid eidem, licet invito, Ciceroni solitudo illa contulerit notum est: fecit enim magnum de summo oratore philosophum; ex quo quantum studiis latinis accreverit, nemo studiosus est qui nesciat.