"The studio hired a historical adviser, Colonel Einhornung, whose job was to ensure that Swedish royalty would not take offence to the film....The colonel did so,   and his voice was cheerfully ignored by Mamoulian and company. The colonel had many complaints about the film's historical inaccuracies, among which were the way the queen is quick to go to bed with a stranger and the fact that the Diet ought not to be seen to clamour for war, as is the case in the early sceneof Christina and her fire-eating courtiers.

He asserted that nobles did not wear light-coloured hose and short wigs, nor would it have been possible for there to have been in Sweden's cold climate the abundant fruits that are displayed in the inn scene.  More recently, George Fraser Macdonald has faulted the script for showing an old Gustavus Adolphus dying on the battlefield of Lutzen, since the king was only thirty-eight when he died, and he also points out that the queen's abdication was not the consequence of a romantic entanglement.

Notwithstanding...Queen Christina does in fact conform to certain aspects of the history of that persiod, through selectively, as represented by the queen's relentless quest for peace, her distaste for dynastic marriage, and her devotion to scholarship." 
from Queen Christina, BFI Classics by Marcia Landy and Amsy Villarejo.