From Tomatoman’s daughter:
Introduced by Dad in 1997. This was the best tasting tomato in Dad’s patch in 2005-2006 and was the best producer to boot! Originated from a tomato named “Hillbilly” given to him by Ruth Marcum of Collinsville, OK, which she received from her brother Ralph Miller of Ohio. Ruth’s seeds grew out three different tomatoes. Through selection, he established a tomato with colors of deep, deep pink with a purplish or violet tinge, hence the “Royal” tag. An exquisite flavor—very complex blend of sweet and tartness, snappy yet smooth. Grows an abundance of 1-pounders. Plants can produce either potato leaf or regular leaf.
Here is some more info about Darrel Merrel, The Tomato Man.