Found this art review in The New York Times archive for a 2004 show called ''Mark Rothko -- A Painter's Progress: The Year 1949'' at PaceWildenstein in New York City.

From the review:

[1949] is the year that [Mark Rothko] finally broke free of the obligation to make interestingly varied compositions and discovered the power of large, simple, symmetrically ordered blocks of color. He began to make the paintings that we now view as classic Rothkos.

I love this next line.

So part of the excitement is seeing the moment when an artist dares to become fully himself.

Take a look through Rothko's work from 1949 for yourself. It's truly exciting to see him come into his own.

Some of my favorite artwork, ever.