Wall paintings perhaps made over half of the painting activities in Bhutan since very old times. Historical records confirm the existence of the art of wall painting as early as the 15th century but the practice probably existed long before then. Old wall paintings, such as the ones found in Tamzhing from the beginning of 16th century, are created directly on the mud wall while most other later wall paintings are done on canvas. Some paintings are done on canvas first and later stuck to the wall but others are done after fixing the canvas on the wall. Some of Bhutan's murals are claimed by international conservationists as being comparable to the works of Michelangelo.