According to the order, it consisted of two infantry regiments (each divided into two battalions with 1,000 volunteers), and two or three cavalry squadrons (150 men in each).
Archduke Friedrich, Duke of Teschen named Major Adam Pietraszkiewicz commandant of the Legion, while his chief of staff was Captain Dionizy Jasienicki.
For unknown reasons, Adam Pietraszkiewicz did not become commandant of the Legion, so his post was offered to Captain Dionizy Jasienicki.
Count Skarbek, who was a very influential person in Galicia, opposed this promotion, and as a result, on 14 September Captain Józef Haller became the new commandant of Eastern Legion.
Most of its volunteers refused to swear allegiance and obedience to the Emperor Franz Joseph I of Austria: only 800 soldiers, most of whom came from Podhale and the Duchy of Teschen, led by Józef Haller and Jan Kozicki, agreed to swear allegiance to Franz Joseph.