Dale Evans, popular singer and actress has passed on at age 88. She had congestive heart failure.

Her husband Roy Rogers was the "King of the Cowboys" and Dale was "Queen of the West". His horse was Trigger and her horse was Buttermilk.

"There's the last of the great ladies from a great era -- the cowboy era," said Fran Boyd, executive director of the Academy of Country Music.

Roy and Dale married in 1947, and together appeared in 35 movies, like "My Pal Trigger," "Apache Rose", and "Don't Fence Me In." Dale wrote their theme song, "Happy Trails to You".

They both starred in their own television show from 1951-1957, "The Roy Rogers Show".

Dale also wrote "The Bible Tells Me So", which became a standard in gospel music.

Roy's and Dale's most recent album was from 1985, "Many Happy Trails". They recorded more than 400 songs.

Rogers passed on at age 86 in 1998. Dale said he was a "a wonderful human being. What a blessing to have shared my life together with him for almost 51 years. He was truly the king of the cowboys in my life."

She was active in Christian evangelism. She wrote a book about Robin, the only child born to the couple. The child had Down syndrome and died before age 2 of complications from having the mumps. The book was called "Angel Unaware".

Starting out, she was a singer in local radio, Memphis, Louisville and Dallas. She advanced in 1940 to national radio with the show, "News and Rhythm."