Arran was posing as a kind of Protestant.

Ambassadors were sent to Henry to negotiate a marriage between his son Edward and the baby Queen; but Scotland would not give up a fortress, would never resign her independence, would not place Mary in Henry's hands, would never submit to any but a native ruler.
The airy castle of Henry's hopes fell into dust, built as it was on the oaths of traitors.

Love of such a religion as Henry professed, retaining the Mass and making free use of the stake and the gibbet, was not, even to Protestants, so attractive as to make them run the English course and submit to the English Lord Paramount.

Some time was needed to make Scots, whatever their religious opinions, lick the English rod.

But the scale was soon to turn; for every reforming sermon was apt to produce the harrying of religious houses, and every punishment of the robbers was persecution intolerable against which men sought English protection.
Henry VIII.