Origin of Immnunization
"And it is a simple thing for the Psylli to tell by the taste of the
poison what kind of snake it was whose bite the healer has mastered."
Marcus Annaeus Lucanus, 39-65 AD describing a tribe in Libya.

The earliest recorded history of an immunization was from the Roman era in a poem written by a Roman poet named Marcus Annaeus Lucanus. In it he describes the greats war(s) of the day and accounts in North Africa that we refer to as Libya today are given. In these reports much mention is made of the snake and it's significance to the culture is readily apparent. The word "snake" appears what seems to be a fairly common word and much is said of them even if only in passing or as metaphor.

So it stood to reason documentation of the practice of taking repeated tiny doses of snake venom to acquire an immunity to it would make sense. Other than war, pestilence or poison were the leading causes of death and interest was high in developing an immunity to these.

It was in fact the Romans that coined the word "immunity" for us, it comes from the Latin "immunitas" and "immunis" which originate in Rome. Originally it was a legal term and one you will still find it in the law to today; "granting immunity" is a well understood legal concept as is "diplomatic immunity". These describe exceptions to British Common Law which is in turn the basis for many legal systems wound the world. acquiring immunity from external sources was the Roman poet Marcus Annaeus Lucanus (ACE 39-65) documentation of the Psylli tribe in what is now Libya practicing acquired immunity to snakebite by repeated ingestion of tiny doses of snake venom.

Here is is in the original Latin with a translation:

Fata trahit, tunc sunt magicae miracula ycntis 
Psyllorumque ingens et rapti pugna veneni. 
Nam primum tacta designat membra saliva, 925 

Quae cohibet virus retinetque in volnere pestem ; 
Plurima tunc volvit spumanti carmina lingua 
Murmure continue, nee dat suspiria cursus 
Volneris, aut minimum patiuntur fata tacere. 
Saepe quidem pestis nigris inserta medullis 930 

Excantata fugit ; sed, si quod tardius audit 
Virus et elicitum iussumque exire repugnat, 
Turn super incumbens pallentia volnera lambit 
Ore venena trahens et siccat dentibus artus, 
Extractamque potens gelido de corpore mortem 935 
Expuit ; et cuius morsus superaverit anguis, 
lam promptum Psyllis vel gustu nosse veneni. 
Hoc igitur tandem levior Romana iuventus 
Auxilio late squalentibus errat in arvis. 
Bis positis Phoebe flammis, bis luce recepta 940 

Vidit harenivagum surgens fugiensque Catonem. 
lamque illi magis atque magis durescere pulvis 
Coepit et in terram Libye spissata redire, 
lamque procul rarae nemorum se tollere frondes, 
Surgere congesto non culta mapalia culmo. 946 

Quanta dedit miseris melioris gaudia terrae. 
Cum primum saevos contra videre leones ! 
Proxima Leptis erat, cuius statione quieta 
Exfegere hiemem nimbis flammisque carentem. 
^ Plutarch's more sober account limits this march to seven days ; Lucan prolongs it to two months.

then the wondrous powers of the people were dis- played, and there was a mighty battle between the Psylli and the poison absorbed. The native begins by marking the part with the touch of his spittle ; this arrests the venom and confines it to the wound ; and then his foaming lips rehearse full many a spell with unbroken muttering ; for the speed of the ailment suffers him not to draw breath, nor does death permit a moment's silence. Often indeed the bane, after it has lodged in the blackened marrow, is expelled by incantation ; but, whenever the poison is slow to obey, and resists when it is summoned forth and commanded to come out, then the healer leans over and licks the bloodless place, sucking up the venom and draining the limbs with his teeth, until victorious he drags out the death from the cold body, and spits it out of his mouth. And it is a simple thing for the Psylli to tell by the taste of the poison what kind of snake it was whose bite the healer has mastered.

So, relieved at last by their aid, the Roman soldiers wandered far and wide over the barren plains. Twice had the moon lost her light and twice regained it, while her rising and setting witnessed Cato lost in the desert.^ But now he felt the sand grow ever firmer under his feet, and the soil of Africa became solid ground again ; and now the leaves of trees began here and there to rise in the distance, and rude huts raised with piles of straw. How the sufferers rejoiced to have reached a better country, when first they saw facing them fierce lions only ! Leptis was the nearest city ; and in those peaceful quarters they spent all winter, unvexed by storms or heat.


Ref: Lucan : the civil war books I-X (Pharsalia), 1928