The Osi or Osii were an ancient tribe dwelling beyond the Quadi, in a woody and mountainous country. But their national customs, as well as their language, were those of the Aravisci, who Tacitus called Pannonians. They were, moreover, tributary to the Quadi and

Sarmatae The Sarmatians (; grc, Σαρμαται, Sarmatai; Latin: ) were a large confederation of ancient Eastern Iranian equestrian nomadic peoples of classical antiquity who dominated the Pontic steppe from about the 3rd century BC to the 4th cent ...

. The exact districts they inhabited cannot be determined, nor do we know whether they had migrated from Pannonia, or whether they were an ancient remnant of Pannonians in those districts.

Tacitus Publius Cornelius Tacitus, known simply as Tacitus ( , ; – ), was a Roman historian and politician. Tacitus is widely regarded as one of the greatest Roman historians by modern scholars. The surviving portions of his two major works—the ...

wrote: :Whether however the Aravisci migrated into Pannonia from the Osi, a German race 'Germanorum natione'' or whether the Osi came from the Aravisci into

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

, as both nations still retain she same language, institutions, and customs, is a doubtful matter; for as they were once equally poor and equally free, either bank had the same attractions, the same drawbacks. ...however in that case Tacitus uses the term "''natio''" to define the Osi in a geographical way, as shown by his other mention of them... :The

Gotini The Gotini (in Tacitus), who are generally equated to the Cotini in other sources, were a Gaulish tribe living during Roman times in the mountains approximately near the modern borders of the Czech Republic, Poland, and Slovakia. The spelling "Got ...

and Osi are proved by their respective Gallic and Pannonian tongues, as well as by the fact of their enduring tribute, not to be

Germans , native_name_lang = de , region1 = , pop1 = 72,650,269 , region2 = , pop2 = 534,000 , region3 = , pop3 = 157,000 3,322,405 , region4 = , pop4 = ...

. Tribute is imposed on them as aliens, partly by the Sarmatæ, partly by the Quadi. The Gotini, to complete their degradation, actually work iron mines. All these nations occupy but little of the plain country, dwelling in forests and on mountain-tops. The ethnicity of the Osi is a matter of debate: some claim they were Germanic, others Celtic, others Dacian.E.g.
Romanian History and Culture
/ref> But most likely the customs, manners, language and ethnicity were a mixture of two of them or all of them as was common in those areas in Central Europe and the Balkans.

References

{{SmithDGRG, title=Osi Ancient peoples of Europe Ancient history of Austria Ancient tribes in Hungary Ancient Slovakia Early Germanic peoples