A cover mattress is an ornamental mattress somewhat just like a 4-poster bed. A typical cover mattress often features posts at each of the 4 corners extending 4 toes high or extra above the mattress. Ornate or ornamental fabric is usually draped across the higher space between the posts and a solid swath of material could create a ceiling, or cover instantly over the bed.
A 4-poster mattress is a mattress with 4 vertical columns, one in each nook, that assist a tester, or higher (often rectangular) panel. This tester or panel will usually have rails to allow curtains to be pulled across the bed. There are a number of vintage 4-poster beds extant relationship to the sixteenth century and earlier; many of these early beds are extremely ornate and are produced from oak. An example of such an early sixteenth-century 4-poster resides in Crathes Fort, which was made for the original citadel house owners within the Burnett of Leys family.