That armor actually is not from the Dark Ages. The Dark Ages were from around 500 CE to 1400CE. During that era the predominant mail was chain mail, not plate. Now there was "plate mail" during that era, but it is not what you have pictured. What was used is known as a "Coat of plate armor", simply an advancement of what the Romans used. Either plated fixed like playing cards over leather, or articulated plated akin to what the Romans used. What you have pictured is a suit of full plate, which was not developed until the Renaissance. Ignore what popular culture says, that is anachronistic in medieval or dark ages armories. Heck, the very name of the organization that reveres that time period recognizes that their own preferences for armor, weapons and tactics does not belong in the time period they love to cosplay. That is why it is called the Society for Creative Anachronism.