Beehive tombs developed from Mycenaean shaft tombs, which first appear around 1600 BC. After about 1500 BC, beehive tombs became more widespread. They were built as corbelled arches, layers of stone and dirt placed closer together as the arch tapers toward the top of the tomb. This style is probably an influence from Minoan tombs. Each tomb usually contains more than one person, in various places in the tomb, and with various grave goods. After a burial, the beehive tomb was covered with dirt, leaving a small mound with most of the tomb underground. They were connected to the surface by a long tunnel, leading to a door consisting of a set of monoliths. Because there are hundreds of such tombs, with more than one associated with each Mycenaean settlement, they were probably not burial places for the aristocracy alone, although the larger tombs, ranging from about 10 meters to about 15 meters in diameter, were likely used for royal burials. The larger tombs presumably contained aristocratic grave goods, but the tombs were pillaged in ancient times.