Each century in a cohort had a signum or battle standard.  It was carried by the signifer, who wore a bear or wolf pelt over his helmet and hanging  down his back.  Just what the various discs and crescents indicated is unknown; there is a theory that the number of discs corresponds to the century's number in the cohort, but this is contradicted by a signum shown on Trajan's Column with seven discs.  There is also a scene of two signa standing side by side, each with five discs--they should be in different parts of the camp if they represent the 5th century of different cohorts.  (And in any case, centuries were not numbered but were known by their centurions' titles, e.g. hastati priores, etc.)  The discs may indicate the number of the cohort, or they may be unit awards for valor, or they may have some other meaning entirely.        Other objects that may appear on the signum include wreaths, plaques with unit nomenclature, images of the emperor, and animal totems.  At the top was either a simple spearhead or a hand, possibly a tradition dating back to the maniple or "handful", a unit of two centuries.        There are at least three metal discs that have been found that may be from signa, but this is not certain so modern reconstructions are based almost entirely on visual evidence.  Two of the discs have rings or loops on the back for the pole to go through, and we have copied this on the crescent and hand.  Our discs are spun steel and came to us from Dan Peterson (the same ones seen in his book!), and they are secured by regular carriage bolts and square nuts, made to look like big rivets.  They are about 6-1/2" in diameter.  I made our hand and crescent from 18-gauge bronze, a little smaller than my own hand, and the tassel is wool yarn.        Many depictions show a pair of "handles" on the bottom part of the pole.  These are actually foot steps, for driving the signum into the ground.        The vexillum was a small banner carried by any detached part of a legion.  It was also used as a cavalry standard.  One original vexillum has been found, red linen painted with a figure of Victory standing on a globe (seen in Connolly's book).  In Roman artwork, any vexillum which isn't just blank (due to loss of painted detail) has only lettering on it.        Our vexillum is red silk with painted letters, about 12" by 16".  At the top the fabric is turned down to form a sleeve, and there's a notch cut in the sleeve at the middle of the back.  On the pole is a simple brass strip formed into loop--that goes into the notch, and a wood dowel crossbar goes through the sleeve and the loop.  A removable pin through the loop and into the crossbar keeps it from sliding around.  Much of this construction is simply guesswork because none of these details survive.   Some depictions show cords running from the ends of the crossbar up to the finial (usually a spearhead).  The fringe is white wool yarn.        Every legion had its aquila, or eagle standard, carried by the aquilifer.  It may have been hollow-cast bronze or silver with gold plating, or maybe worked from gold or gilded silver sheet.  Another standard called the imago was a small bust of the emperor.  Legio XX does not yet have an aquila, though Legio XXIV does.        When not being carried, the unit's standards were stored in a special shrine in the principia or headquarters building.  They were considered to be sacred objects, and sacrifices were made to them.  The loss of any standard in battle, particularly the aquila, was the worst possible disgrace for a unit.