Fronto, Letters to Marcus Aurelius 2.2.6
versus quos mihi miseras remisi tibi per Victorinum nostrum atque ita remisi: chartam diligenter lino transui, et ita linum obsignavi ne musculus iste aliquid aliqua rimari possit. nam mihi ipse de tuis hexametris numquam quicquam impertivit, ita est malus ac malitiosus. sed ait te de industria cito et cursim hexametros tuos recitare: eo se memoriae mandare non posse. remuneratus est igitur a me mutuo; paria habet ne ullum hinc versum audiret. memini etiam te frequenter, ne cuiquam versus tuos ostenderem admonuisse.
I have sent back to you with our Victorinus the verses which you sent me, and this is how I’ve sent them: I’ve carefully sewn across the paper with thread, and sealed the thread in such a way that that little mouse can’t poke his nose in anywhere at all. For he has never shared anything about your hexameters with me – that’s how mischievous and malicious he is. But he says that you intentionally recite your hexameters quickly and hastily, so that he can’t commit them to memory. Therefore he’s been paid back in return by me; he has like for like, not hearing a single line from here. I also recall that you have frequently cautioned me not to show your verses to anyone.