That is something I also can't answer. If it helps, I know that there are natural dyes from plant sources
They likely used Natural dyes, which can be from vegetables and plant sources like roots, bark, leaves, berries and wood. You can also find dyes in fungi and lichens!
I love to color my hair. I recently colored it purple. How interesting! Did you do it yourself or did you go to a professional? I did it myself at home. Do you have any advice on how to maintain it? I don't have any advice. What I can tell you is that in 2011 alone, at-home coloring in the US reached 1.9 billion dollars. Wow, that's a lot of money. It can be stressful dying your hair by yourself. I wonder how they dyed it in ancient times.
The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, and wood—and other biological sources such as fungi and lichens.