Leonardo di Piso's Liber Abaci
The Latin text is compiled into a collection called Scritti di Leonardo Piso by Boncompagni in 1857.
Link to Latin text in archive.org
Quot paria cuniculorum in uno anno ex uno pario germinentur.
Quidam posuit unum par cuniculorum in quodam loco , qui erat undique pariete circundatus, ut sciret, quot ex eo paria germinarentur in uno anne: cum natura eorum sit per singulum mensem aliud par germinare; et in secundo mense ab eorum natiuitate germinant.
A certain man placed one pair of rabbits in a certain place, which was surrounded all around by a wall, so that he might know how many pairs from them might be sprouted up in one year's time.
While their nature is to multiply with another throughout a single month, they also procreate in the second month from their birth.
Quia suprascriptum par in primo mense germinat, duplicabis ipsum, erunt paria duo in uno mense. Ex quibus unum, scilicet primum, in secundo mense geminat; et sic sunt in secundo mense paria 3;
Because the pair written about above multiplies in the first month, you will double it (maybe "when you duplicate it"), (then) there will be two pairs in one month. From these, it doubles with one, namely the first, in the second month. And so there are in the second month 3 pairs.
ex quibus in uno mense duo pregnantur ; et geminantur in tercio mense paria 2 coniculorum ; et sic sunt paria 5 in ipso mense;
After which in one month, two are impregnated. Then 2 pairs of rabbits are doubled in the third month. And so there are 5 pairs in that month.
ex quibus in ipso pregnantur paria 3; et sunt in quarto mense paria 8; ex quibus paria 5 geminant alia paria 5: quibus additis cum parijs 8, faciant paria 13 in quinto mense;
From which the three pairs impregnate among themselves, then there are 8 pairs in the fourth month. After which 5 pairs double with the other 5 pairs. When these are added together with the 8 pairs, they would make 13 pairs in the fifth month.
ex quibus paria 5, que geminata fuerunt in ipso mense, non concipiunt in ipso mense, sed alia 8 paria pregnantur; et sic sunt in sexto mense paria 21;
After the 5 pairs, the ones that have been multiplied in that month, do not conceive in that month, but the other 8 pairs are impregnated. And so there are 21 pairs in the sixth month.
cum quibus additis parijs 13, que geminantur in septimo , erunt in ipso paria 34 ; cum quibus additis parijs ii, que geminantur in octauo mense, erunt in ipso paria 55;
With the 13 pairs added together, which are doubled in the seventh month, there will be 34 pairs in that month. When these pairs are added together, which are doubled on the 8th month, there shall be 55 pairs.
cum quibus additis pariis 34, que geminantur in nono mense, erunt in ipso paria 80; cum quibus additis rursum parijs 55, que geminantur in decimo, erunt iu ipso paria 144; cum quibus additis rursum parijs 89, que geminantur in undecimo mense, erunt in ipso paria 233. Cum quibus etiam additis parijs 144 , que geminantur in ultimo mense, erunt paria 377;
When the 34 pairs are added together, which are doubled on the ninth month, there shall be 80 pairs in that month.
When those 55 pairs are added back, which are doubled in the 10th month, there shall be 144 pairs in that month.
When the 90 pairs are added back again, which are doubled on the tenth month, there shall be 233 pairs.
When even these 144 pairs are added, which are doubled in the final month, there shall be 377 pairs.
et tot paria peperit suprascriptum par in profato loco in capite unius anni. Potes enim indere in hac margine, qualiter hoc operati fuimus, scilicet quod iunximus primum numerum cum secundo, uidelicet 1 cum 2; et secundum cum tercio; et tertium cum quarto; et quartum cum quinto, et sic deinceps, donec iunximus decimum cuin undecimo, uidelicet 144 cum 233; et habuimus suprascriptorum cuniculorum summam, uidelicet 377 ; et sic posses facere per ordinem de infinitis numeris mensibus.
And so the pairs birthed the pair written about above in the aforementioned place at the head of the first month.
You are able to (read?) in this margin how we have worked namely that we joined the first with second, and the second with third, and fourth with fifth, and so on until we joined the 10th with the 11th, namely 144 with 233.
And we have the sum of the aforementioned rabbits, namely 377.
And thus you would be able to work through the order for an infinite number of months.