Standard ancient Roman uniform consisted of a tunic, a cloak and sandal-type boots, resulting in a [look like this](https://group3digitalliteracy.files.wordpress.com/2013/03/6.jpg). Now, this is all very well for Mediterranean climates but I really cannot fathom how they got along with this clothing in Northern Europe (Germania, Britannia, Northern Gaul, etc.). Was there another type of uniform more suitable to cold climates?

I know there is a [theory](http://www.dailymail.co.uk/sciencetech/article-2171973/Tree-ring-study-proves-climate-WARMER-Roman-Medieval-times-modern-industrial-age.html) that the temperatures were then higher than today but at least the article I've linked to talks about a difference of 1 degree Celsius - not enough to make one warm and cozy in a tunic on a cold North European winter day.

So what was the Romans' trick? Were they supermen or something?