The Fähnlein (in Swedish: fänika) was an infantry unit approximately equivalent to the company or battalion which was used in parts of Europe during the Middle Ages.
The size of the unit varied; originally a Fähnlein could consist of as many as 1,000 soldiers, but numbers were generally less, around 500.
In the 17th century, some Fähnleins or fänikor would have a strength of only 100 to 200 men, and it was at this time that the designation "company" came into widespread use.
As a formed unit, a Fähnlein consisted of around 400 Landsknechte, commanded by a captain (Feldhauptmann, Hauptmann or Kapitän).
At the beginning of the 17th century, i.e. before the Thirty Years' War a Fähnlein in Germany was supposed to have the following strength: Under Charles V the staff of a German Fähnlein was as follows: This structure was also called the prima plana (Latin for "first sheet") because these appointments were on the first page of the muster lists.