A hauberk is a maille shirt with long sleeves (between elbow and wrist-length), reaching to at least mid-thigh length when belted. Some hauberks reached to below the knee when belted. Hauberks should be front- and back-split. Such longer hauberks should be worn over a padded akheton, either with a maille coif and padded arming cap or an integral coif.
Late Anglo-Saxon hauberks
Eleventh-century English (and probably also viking) hauberks seem to have been tied around the knees and upper leg to provide secure protection for the leg. There are quite a few depictions of this, most notably from the Bayeux Tapestry, but also a fragment of stone sculpture from Winchester (dated c.1050).
Later medieval hauberks
Twelfth century hauberks, "cap a pie"
Hauberks with integral maille coifs and maille mittens (effectively chainmail ‘hoodies’) were particularly popular during the twelfth century, but went out of favour in the thirteenth, being replaced by separate coifs.
This crusader is wearing the full wargear of the thirteenth century, clad 'cap a pie' (head to foot) in maille armour.