Mycenaean pottery is the pottery tradition associated with the Mycenaean period in Ancient Greece. It encompassed a variety of styles and forms including the stirrup jar. The term "Mycenaean" comes from the site Mycenae, and was first applied by Heinrich Schliemann. The term "Mycenaean" has been imposed upon a matrix of abbreviational archaeological names, which amount to an archaeological code. This code had been standardized by various archaeological conventions. An archaeological name is the name given to a layer (or layers) at a site that is being professionally excavated. Archaeology depends on the fact that layers of types of soil and content accumulate over time, which undisturbed, can yield information about the various times. Typically an archaeological name identifies the site and the relative position of the layer. Predetermined knowledge of the layer provides information about the time and other circumstances of the artefacts found within it. Pottery is an especially good diagnostic of time period when found within a layer. It is not perfect or certain, however. The custom of naming layers began with Heinrich Schliemann's excavations at Troy. He identified cities layered on top of one another: the first, the second, etc., starting at the bottom of the heap. These later became Troy I, Troy II, etc. Arthur Evans, excavator of Knossos and a friend of Schliemann's, followed this custom at Knossos; however, foreseeing that the layers there would likely be repeated elsewhere, he preferred the name "Minoan" (abbreviation M) over Knossos, as he believed that one of the high kings of Crete ruling from Knossos was the legendary King Minos. He also chose Minoan for the name of the civilization. Subsequently, Carl Blegen, excavator of Pylos, who found the main cache of Linear B tablets on his legendary first day's dig, extended Evans' system to "Helladic" (adjective of Hellas, abbreviation H) and "Cycladic" (adjective of Cyclades, abbreviation C). The Cyclades are a specific number of islands in the Aegean Sea.