The effort coincides with the 1,000th anniversary of his birth.
Alex Johnstone, one of the group's members said Wednesday Macbeth, who ruled Scotland from 1040 to 1057, had a good reputation until it was "maligned by William Shakespeare's play" written 1605-06.
He said Shakespeare rewrote history in "Macbeth" in a way that would appeal to King James VI of Scotland, who became James I of England in 1603, by picturing Macbeth as driven to dire deeds including murder by the prophesies of witches. James VI reportedly believed in witches.
"Macbeth unified the country in a time of war and promoted Christianity," Johnstone said. "He was always perceived as a good king, and we want to see him perceived that way again."