From My Research...

At the turn of the century a woman named Maud Humphrey created artwork that was extremely popular. Some of it appeared on calendars, advertisements, children's books, and greeting cards. You can see why people loved her work.

She was a modern American woman of the times, active in the suffragist movement and a working wife.

She even kept her maiden name. 

Her son was Humphrey Bogart.

I couldn't make a Celtic connection, but this came up while I researching the time period of my novels and I wanted to share.