Knowth. The exhibit then covers the introduction of metallurgy into Ireland around 2500 BC, with early copper implements. From the later Bronze Age period there is an impressive array of bronze axes, daggers, swords, shields, cauldrons and cast bronze horns (the earliest known Irish musical instruments). There are a few very early Iron weapons. Wooden objects include a large dugout logboat, wooden wheels and cauldrons and ancient reed fishing equipment. Bronze age and goldwork The NMI's collection of Bronze Age goldwork ranges from c. 2200 to 1800 B.C and is considered one of the "largest and most important" in Western Europe. The gold was recovered from river gravel, and hammered into thin sheets used to create objects such as crescent shaped collars (Gold lunula), bracelets and dress-fastners. Most of the goldwork is probably jewellery, but many of the objects of are of unknown (possibly ritual) function. By the middle Bronze Age new goldwork techniques were developed; from around 1200 BC a great variety of torcs were produced from twisting bars of gold. Items from the late Bronze Age, starting in 900 BC, include solid gold bracelets and dress-fasteners as well as large sheet gold collars, ear-spools and a necklace of hollow golden balls. Bog bodies (Iron age) The museum contains a number of well-preserved Irish bog bodies dating to the Iron Age, some of which are believed to have been ritualistically sacrificed. The archaeologist Eamonn Kelly developed the theory that the bodies were tribal kings sacrificed by the community after failed in their kingship, drowned in pools of water at the boundary points of the tribal territory. Some seem to exhibit evidence of the so-called threefold death practice of strangulation, wounding and drowning. The bog bodies in the collection are Cashel Man (c. 2000 BC), believed to be the oldest fleshed bog body found in Europe, Gallagh Man (470-120 BC), Clonycavan Man (392 to 201 BC), Old Croghan Man (362 to 175 BC), and Baronstown West Man (242 to 388 BC). The bodies in the NMI's collection are males aged 25 to 40 years old who died in violent, and perhaps ritual circumstances. The withy hoop found around Gallagh Man's neck was probably used as a garrotte to strangle him; Although he may have been a criminal who was executed, the willow rope strongly suggests ritual sacrifice as they often appear for this purpose in early Irish mythological stories. The