The treatise De Architectura by the Roman architect Vitruvius (born c. 80–70 BC, died after c. 15 BC), is the only book about architecture having come down to us from Antiquity and it was widely used during the Renaissance as a guide for constructing buildings on classical principles. It is not much read nowadays and it was in a book about Renaissance Europe by John Hale that I found the following text. Building on previous writers, Vitruvius narrates how society begun: there was a time that people lived like animals (ut ferae) in the open. At some time fire was discovered and people gathered around this fire and started to communicate to each other. Initially they were nodding and pointing and used inarticulate sounds, but gradually language developed. Being an architect, he tells also how the construction of buildings developed. The way Vitruvius describes or rather imagines how this has happened makes us smile, but he is certainly right in postulating that fire and language have been important constituents for the growth of culture.
Vitruvius, De Architectura , 2, 1-2
 Homines vetere more ut ferae in silvis et speluncis et nemoribus nascebantur ciboque agresti vescendo vitam exigebant. Interea quondam in loco ab tempestatibus et ventis densae crebritatibus arbores agitatae et inter se terentes ramos ignem excitaverunt, et eius flamma vehementi perterriti, qui circa eum locum fuerunt, sunt fugati. Postea re quieta propius accedentes cum animadvertissent commoditatem esse magnam corporibus ad ignis teporem, ligna adicientes et id conservantes alios adducebant et nutu monstrantes ostendebant, quas haberent ex eo utilitates. In eo hominum congressu cum profundebantur aliter e spiritu voces, cotidiana consuetudine vocabula, ut optigerant, constituerunt, deinde significando res saepius in usu ex eventu fari fortuito coeperunt et ita sermones inter se procreaverunt.  Ergo cum propter ignis inventionem conventus initio apud homines et concilium et convictus esset natus, et in unum locum plures convenirent habentes ab natura praemium praeter reliqua animalia, ut non proni sed erecti ambularent mundique et astrorum magnificentiam aspicerent, item manibus et articulis quam vellent rem faciliter tractarent, coeperunt in eo coetu alii de fronde facere tecta, alii speluncas fodere sub montibus, nonnulli hirundinum nidos et aedificationes earum imitantes de luto et virgulis facere loca quae subirent. Tunc observantes aliena tecta et adicientes suis cogitationibus res novas, efficiebant in dies meliora genera casarum.
vetere more: in an earlier way of life (as opposed to the current)
nascor natus: to be born
vescor (+ abl.) to feed
vitam exigo: to spend life
densae crebritatibus arbores: trees dense by closeness, i.e. standing close together
tero trivi tritus: to rub
perterritus: very frightened
animadverto: to notice
comoditas -atis (f.): benefit
tepor teporis: lukewarmness, tepidity
adicio acieci adiectum: to add
id: neuter, but of course referring to the fire
nutus nutus (m.): nod, sign
profundebantur aliter e spiritu voces: expressed words differently by breath, i.e. there was not a common language but each individual made his own words.
ut optigerant: as they (the vocabula) happened to occur, i.e. at random
ex eventu: eventually, finally
fari: to speak (this word is only found in a limited number of forms and for does not occur.)
fortuito: by chance
conventus –us (m.): assembly
convictus –us (m.): social intercourse
pronus: bend forward
articuli –orum: the fingers
coetus –us (m., mostly written coitus): coming together
frons frondis (f.): leafy branch
fodio fodi fussum: to dig
hirundo –inis (f.): swallow
aedificatio –onis (f.): building structure
virgula: a little twig
sub-eo subii subitum: to enter, inhabit
in dies: in due course
Translation by Joseph Gwylt (1826)
Mankind originally brought forth like the beasts of the field, in woods, dens, and groves, passed their lives in a savage manner, eating the simple food which nature afforded. A tempest, on a certain occasion, having exceedingly agitated the trees in a particular spot, the friction between some of the branches caused them to take fire; this so alarmed those in the neighbourhood of the accident, that they betook themselves to flight. Returning to the spot after the tempest had subsided, and finding the warmth which had thus been created extremely comfortable, they added fuel to the fire excited, in order to preserve the heat, and then went forth to invite others, by signs and gestures, to come and witness the discovery. In the concourse that thus took place, they testified their different opinions and expressions by different inflexions of the voice. From daily association words succeeded to these indefinite modes of speech; and these becoming by degrees the signs of certain objects, they began to join them together, and conversation became general.
Thus the discovery of fire gave rise to the first assembly of mankind, to their first deliberations, and to their union in a state of society. For association with each other they were more fitted by nature than other animals, from their erect posture, which also gave them the advantage of continually viewing the stars and firmament, no less than from their being able to grasp and lift an object, and turn it about with their hands and fingers. In the assembly, therefore, which thus brought them first together, they were led to the consideration of sheltering themselves from the seasons, some by making arbours with the boughs of trees, some by excavating caves in the mountains, and others in imitation of the nests and habitations of swallows, by making dwellings of twigs interwoven and covered with mud or clay. From observation of and improvement on each others' expedients for sheltering themselves, they soon began to provide a better species of huts.