Norwegian-Swedish Union Royal Flag (1844-1905)

The royal flag of 1844-1905 did not have the union arms [of Sweden-Norway] on a square panel on the centre of the arms, as the present Swedish royal flag has the greater state arms, but the arms were right upon the cross. A picture of this flag is shown in Jan von Konow: "Svenska flaggan - När? Hur? Och varför?" [knw86a], on page 19. The groundpattern is the Swedish three-tounged flag with the union mark in the canton. The colours are darker and the cross is broader than in the present flag.
Elias Granqvist, 2001-Jan-25

The white square was reintroduced after 1905. Prior to 1844 Swedish royal flags had the arms set on a white field over the intersection of the arms. When a new model for the royal flag was introduced along with other revised flags in the flag system of 1844 the box disappeared. 1844 was the year the union mark was set into the Swedish and Norwegian flags.

Swedish royal flags are accounted for in a nice publication: Torsten Lenk: "Svensk kunglig flagga," Livrustkammaren: Journal of The Royal Armoury, Vol. 6, No. 11-12, 1954, pp. 180-212
Jan Oskar Engene, 2001-Jan-26

This [the upper image above] is the Norwegian royal standard of 1844 pattern. The coat of arms of the dual kingdom was set in the crossing point of the cross but without the otherwise usual white panel.
Željko Heimer, 28 July 2002

Note that these were the arms of the united kingdoms (plural). The union was one between two separate kingdoms, hence the two crowns over the shield.

There was only one version of the union arms. In the 1901 flag regulations there is a depiction of the Royal flag with Norway occupying the first half of the shield, but this is something of a myste

Norwegian-Swedish Union Royal Flag (1844-1905)

History of the Flag