colour image into black and white

[fishswim43]

I have this image > upload.wikimedia.org/wikipedia/commons/2/28/Coat_of_Arms_of_Great_Britain_(1714-1801).svg I would like to turn this into a black and white image. I have tried this by going to image > Adjustment and Threshold but I am not sure how to turn the unicorn/horse black.

[kennykro]

Do you want the whole image to be black and white or just the horse to be black?

If you want the whole image to be black and white go to image>adjustments>hue saturation. Then drag the saturation slider all the way to the left.