Authenticity, or being ‘genuine,’ (Oxford Dictionaries, no date) is being true to your self and creating something you believe in. Something majorly uninfluenced by other people opinions. However, ‘true’ authenticity is impossible because of the influences which mould a person.
What makes a person authentic is created and grown through their encounters and what they pick up through their life. This makes it impossible to be truly authentic in the sense they are untouched in their opinions. What matters, in terms of authenticity, is that they are not flimsy in their views and stick to what they know and how they like to work.
This means even if they want to change their own ‘style,’ they are staying authentic to their personal desires rather than those of others. A strong character can stay authentic to themselves, in this sense, understanding that others impact them but it is themselves who make the biggest impact.
Modernism, in a sense, was authentic as a movement too. The artists made the move from religious art, made by only the highest classes, into art for a new age after WW1 and in the midst of WW2, notably the Bauhaus, creating what they wanted rather than what people thought they wanted, which in time opened up the artistic world to a whole new view.