SAN BARTOLO, GUATEMALA.- An accidental find by an archaeologist in Guatemala has turned out to be the oldest-known Mayan wall painting. The mural, which is 1.2m long, dates from 100 AD and is being seen as one of the most important finds in Mayan archaeology for decades. Archaeologist William Saturno was looking for some shade at the pyramid site in San Bartolo when he shone his torch down a tunnel dug by looters - and saw the painting. The discovery in March last year has just been reported in the April edition of National Geographic magazine. "This painting is among the most important finds in Maya archaeology in the last few decades," said Mr. Saturno, a University of New Hampshire lecturer. "It opens a window into the mythological and courtly life of the ancient Maya during the pre-Classic period." The mural, which is in a 24m-high pyramid, was confirmed as Mayan by comparing it with other work from the civilization. The only previously known paintings from this period are from Tikal, one of the largest Maya ceremonial and political centers yet discovered in Guatemala - but they are not nearly as large or well preserved.