King of the (Germanic nation of the) Franks, 768-814, founder and emperor (800-814) of the Holy Roman Empire (800-1807); son of the Frankish king Pippin the Short (714-768) and grandson of the Frankish king Karl Martell ("the Hammer," i.e., of the Muslim Saracens; 689-741)

Son of Charlemagne and co-regent with him (813-814), then sole emperor of the Holy Roman Empire until death in 840.

Eldest son of Ludwig the Pious by the latter's first wife, and Holy Roman Emperor (840-855), king of the middle third of the Empire from Frisia to Italy, inclusive.

Third son of Ludwig the Pious by the latter's first wife, and king of the East Franconian (i.e., basically German), eastern third of the Empire.

Fourth son of Ludwig the Pious - by the latter's second wife, and king of the West Franconian (i.e., basically French), western third of the Empire. Holy Roman Emperor 875-877.

Grandson of Charlemagne through the latter's daughter Berhta's premarital liaison with Angilberht, Charlemagne's secretary of state. Famous Frankish historian.

Ergo (ante diem) XVI (sextum decimum) Kalend(as) Mart(ias), Lodhwicus et Karolus in civitate, quæ olim Argentaria vocabatur, nunc autem Strazburg vulgo dicitur, convenerunt, et sacramenta, quæ subter notata sunt, Lodhwicus Romana, Karolus vero Teudisca lingua juraverunt.

Therefore on the 16th day before the Calends of March (i.e., February 14th) [A.D. 842], Ludwig and Karl met in the city which was formerly called Argentaria, but now in the venacular tongue Strassburg, and swore the oaths which are written below - Ludwig in the Romance (i.e., Old French, actually Proto-French, the earliest recorded "French"), but Karl in the German language [specifically, in the Rhenish Franconian dialect of Old High German].

Ac sic ante sacramentum, circumfusam plebem alter Teudisca, alter Romana lingua allocuti sunt.

But before the oaths, they addressed the people gathered around, the one in the German, the other in the Romance tongue.

Lodhwicus autem, quia major natu, prior exorsus sic cœpit:  « Quotiens Lodharius me et hunc fratrem meum », etc.

Ludwig [the German ruler], namely, because he was the elder, began first thus: “How often Ludher me and my brother here,” etc.

Quumque Karolus hæc eadem verba Romana lingua perorasset, Lodhwicus, quoniam major natu erat, prior hæc deinde se servaturum testatus est :

When Karl [the French ruler] had spoken the same words in the Romance language, Ludwig, because he was the elder, swearing first, swore that henceforth he would hold to these things:

Pro  deo    amur                          et
For  God's  love (= for the love of God)  and

pro        Christian  poblo     et   nostro
for  (the) Christian  people's  and  our

commun  salvament,  d'ist      di
common  salvation,  from-this  day

in          avant,   in  quant
into (the)  future,  in  however-much

Deus  savir      et   podir
God   knowledge  and  power

     me  dunat,  si  salvarai              eo
(to) me  gives,  so  will give protection  I

c'ist    meon  fradre   Karlo  et    in  ajudha
to-this  my    brother  Karl   both  in  aid

et   in  cadhuna  cosa,   si  cum      om
and  in  every    thing,  so  as   (a) man

per  dreit  son  fradra   salvar      dist,
by   right  his  brother  to protect  ought,

in  o       quid  il       me altresi
in  so-far  that  he  (by) me likewise

fazet,     et   ab    Ludher  nul  plaid
shall do,  and  with  Ludher  no   negotiation

numquam  prindrai         qui
never    shall undertake  which

          meon  vol       c'ist
(through) my    volition  to-this

meon  fradre   Karle  in  damno  sit.
my    brother  Karl   of  harm   may be.

Quod quum Lodhwicus explesset, Karolus Teudisca lingua sic hæc eadem verba testatus est :

When Ludwig [the German ruler] had finished this, Karl [the French ruler] swore these same words in the German language thus:

In               Godes  minna
For the sake of  God's  love

ind  in  thes  Christānes  folches
and  in  the   Christian   people's

ind  unsēr  bēdhero  gehaltnissi,
and  our    both's   salvation,

fon   thesemo  dage  frammordes,
from  this     day   forwards,

sō  fram  sō   mir    Got  gewizci
so  far   as   to me  God  knowledge

indi  mahd   furgibit,  sō  hald'ih
and   power  gives,     so  (will) protect I

thesan  mīnan  bruodher,  sōso   man
this    my     brother,   so-as  one

mit  rehtu  sīnan  bruodher  scal,
by   right  one's  brother   ought to,

in  thiu      thaz  er       mig  sō
in  thus-far  that  he  (by) me   thus

      sama  duo (= subjunctive mood),  indi
(the) same  do,                        and

mit   Lūdhēren  in    nohheiniu  thing
with  Ludher    into  no         negotiation

ne   gegango,      the,              mīnan
not  (will I) go,  which,  (through) my

willon,    imo      ce  scadhen  werdhēn.
volition,  for him  to  harm     would turn.

Sacramentum autem, quod utrorumque populus, quique propria lingua, testatus est, Romana lingua sic se habet :

The oath, however, which the people of both swore, each in its own language, is in the Romance tongue thus:

Si   Lōdhwīgs        sagrament,     que
If   Ludwig    (the) loyalty-oath,  which

     son  fradre   Karlo  jurat,
(to) his  brother  Karl   (he) has sworn,

conservat,  et   Karlus  meos  sendra
keeps,      and  Karl    my    lord

de  suo  part  non  los  tanit,  si  jo
on  his  part  not  it   keeps,  if  I

returnar      non  l'int          pois:
to turn away  not  him-therefrom  am able:

ne       jo  ne   neuls  cui   eo  returnar
neither  I   nor  none   whom  I   to turn away

int        pois,     in  nulla  ajudha
therefrom  am able,  of  no     assistance

contra   Lōdhwīg  nun       li   ju  er
against  Ludwig   not  (to) him  I   will be.

Oba  Karl  then  eid,   then   er
If   Karl  the   oath,  which  he

     sīnemo  bruodher  Lūdhwīge  gesuor,
(to) his     brother   Ludwig    has sworn,

geleistit,  indi  Lūdhwīg  mīn  hērro
fulfills,   and   Ludwig   my   lord

           then   er       imo  gesuor,
(the  one) which  he  (to) him  has sworn,

forbrihchit,  ob  ih  inan  es
breaks,       if  I   him   therefrom

irwenden      ne   mag,      noh      ih  noh
to turn away  not  am able,  neither  I   nor

thero    nohhein  then  ih  es
of them  none     whom  I   therefrom

irwenden   mag,  widhar   Karle,        imo
turn away  can,  against  Karl,   (for) him

ce       follusti             ne   wirdhit.
into (a) means of execution   not  will turn.

Quibus peractis, Lodhwicus Rhenotenus per Spiram et Karolus juxta Wasagum per Wīzzūnburg Warmatiam iter direxit.

When these things were over, Ludwig [the German ruler] made his way downstream along the Rhine through Speyer and Karl [the French ruler] his along the Vosges through Weissenburg to Worms.