From The Capirola Lute Book, f.3v., translation by Federico Marincola (reproduced with the permission of the author):

The strings are made from the gut of 'castroni' [in Queen Anna's "New World of Words", an Italian/English dictionary published in London in 1611, the word 'castrone' is translated as 'a wether or ewe mutton'], and the gut is always thicker on one hand than it is on the other, so all the hanks [in the manuscript 'iavete'; 'gavetta' is rather old fashioned Italian meaning a 'hunk of gut strings for musical instruments'] have one hand thicker than the other.

When you tie the string on the bridge from the thicker end, it always becomes flatter (as you play higher on that string up the fingerboard). Turning the string the other way round, that is tying it from the thinner end, it will become sharper. However, if they are strings from Munich ['Corde da Monaco' in the original could mean both 'strings from Munich', or 'Monk's strings'. I personally do not see what connection could exist between a monk and a gut string] they do not have this characteristic as they always become sharper (the higher you play on the fingerboard).

When you put on the 'contrabaso' (6th course) and the 'bordon' (5th course), then tie them on the bridge from the thicker end. As I said, they will become flatter (the higher you play on that string). However, be careful to tie the 'tenor' (4th course), 'mezane' (strings of the 3rd course) and 'sotane' (strings of the 2nd course) the other way round, that is to tie them to the bridge from the thinner end. As you know, the 'mezane' are (already) a flat course, and if you tie them from the thicker end like the 'contrabaso' and the 'bordon' they will be (too) flat, and you will never be able to tune them. So, you should tie them the other way round, that is from the thinner end, as I already said, and then tune the 'contrabaso' at the third fret with the 'mezane' at the first fret.

You must understand that this (problem) is more acute with thin strings than with thick ones, and even more so with the strings used 'da ganzer' [the 'ganza', from the renaissance French word 'ganse', was a kind of gut string used to adorn dresses; this is found in 'Dizionario Etimologico Battisti-Alessio'] and others which are not from Munich, as I already said.

I shall repeat how to tie the strings on a lute: the 'contrabaso' and the 'bordon' from the thicker end, the 'tenor', 'mezane' and 'sotane' from the thinner end. This is the secret method of Vincenzo Capirola for tying strings on the lute [it does not give any instruction on how to tie the first course, probably because being a very thin string it is very difficult to decide which end is thicker than the other].

When you pluck a string, to check if it is good and right to put on the lute, pluck it with the right hand. As, when you play, you pluck it with the right hand from the (side of the) bridge. The longer end, or better, the rest of the hank of string should be held by the left hand. A good string makes two lines (which run) from one end to the other (of the string when plucked), and remember to tie the correct end of the string on the bridge. The string which makes three lines, which run from one end to the other (of the string) is still a very good one. Be always very careful to pair (the string) with another one of the same kind: if it makes three lines, pair it with another one which makes three lines; in this way (the two strings) will be in tune, and will not sound false. If, for instance, you cannot tune the 'sotane' or 'mezane', even if they are good, turn the end of the strings the other way round.

For the already mentioned reasons you should then (be able to) tune them. In fact, with the thin strings, very often we cannot be sure which end is the thinner or the thicker one, to tie on the bridge, and for this reason we cannot tune it. If you turn the ends of a string the other way round, you will find that (the string) works better in one position than the other.

If, for instance, when you tie the string, you leave in front of the bridge one inch of false string you will not be able to tune it and the whole string is false. So, take off the string, pluck it again and try and check it. If one of the 'mezane' or the 'sotane' is, by coincidence, thicker than the other, always put the thicker one uppermost. If you pair a false string with a good one, you will never be able to tune them, and you will just have two false strings.

If a good lute has the nut slightly higher than it should be it becomes more difficult to play. If, because of a crack, you need to get a new (nut), be careful to have it of the same height (as the previous one), because, if it is higher, it makes the lute more difficult to play. So, be careful not to lose (the pieces of the broken nut).

Witness the miracle I saw in a lute that I had: the nut was slightly lower than it should have been, the 'canto' (1st string) was too low (on the fingerboard), and the lute sounded mute. I raised it to the proper height and amazingly, the lute came alive.

Consider how important the nut is on the lute!

(Always) note the thickness of the strings which are suitable for (your) lutes, at least the thickness of the three thicker strings, which are the 'contrabaso', the 'bordon' and the 'tenor'. From these three you can, then, work out (the thickness for) the other strings. Different lutes need strings of different gauges; some need thick (strings), others thin (ones) - the thickness of the strings makes the lute sound good or bad.