Boii
Noun
Meaning
Boii pl (plural only)
(historical) A Gallic tribe of the later Iron Age.
Examples
After the loss of their capital, according to Strabo, a large portion of the Boii left Italy.
Invading the Po Valley with a large army, they drove out the Etruscans and resettled it, the Boii taking the right bank in the center of the valley.
Later on, they attacked the city of Noreia (in modern Austria) shortly before a group of Boii (32,000 according to Julius Caesar - the number is probably an exaggeration) joined the Helvetii in their attempt to settle in western Gaul.
Such a connection is possible if the original form of Boii belonged to a tribe of Proto-Indo-European speakers long before the time of the historic Boii.
This is the only "written source" provided by the Boii themselves.
This makes it much more likely that the Cisalpine Boii had actually originated from Bohemia rather than the other way round.