Erasmus, letter to Peter Gillis (October 6, 1516, tr. Francis Morgan Nichols):
Most of our diseases proceed from the mind, and you will be less upset by the labours of study, if you regulate your studies by reason. Arrange your library, and all your letters and papers, in certain settled places. Do not allow yourself to be attracted now to one author and now to another, but take one of the best in your hands with no intention of letting him go until you have come to the last page, noting, as you go on, whatever seems worth remembering. Lay down for yourself a definite scheme of life, determining what you want to do, and at what hours; and do not crowd one thing upon another without finishing what you begin first; in this way you will lengthen your day, which is now almost totally lost. And whereas you find fault with your memory, you will do well, in my opinion, to make a diary for each year,it is no great trouble to do so,and note down daily, in a word or two, if anything has taken place that you wish not to forget.Matthias Stom, Young Man Reading by Candlelight
Plerique morbi nobis ab animo proficiscuntur, et minus offenderis studii laboribus, si ratione studia tua modereris. Bibliothecam tuam, epistolas ac schedas omneis in certos nidulos redigas, neque temere nunc in hunc, nunc in illum autorem rapiaris, sed unum aliquem ex praecipuis in manus sumito, non relicturus prius, quam ad calcem usque perveneris, annotatis interim, quae digna memoratu videantur. Certum aliquod vitae genus ipse tibi praescribito, quid quibus horis agere velis. Nec alia super alia congere, nisi prioribus explicatis: ita diem, qui nunc pene totus intercidit, tibi reddideris longiorem. Et quoniam incusas memoriam, mea sententia profuerit, si in singulos annos fastos pares, non est res magni negocii, singulisque diebus annotes verbo, si quid extiterit, quod nolis oblivisci.