Ontario was the first province to pass an automobile registration law and start province-issued plates in 1903.  These first issues were undated leathers in the shape of a shield.  This 1903 series was replaced by rubber plates in 1905, issued through 1910.  1912-20 plates feature the provincial coat-of-arms.  Two crowns were added in 1937 in honor of the coronation of King George VI, and one crown has remained ever since except for 1951-52.  The earliest of the two currently valid base plates began issue in 1973.