From the early 17th century it became a Frisian tradition that a man asked his beloved to marry him by presenting her with a coin knotted into a costly cloth. This cloth is named knottedoek after the special knot, knotte. If the girl drew the knot tighter, they considered themselves engaged. The knottedoek was later replaced by a small textile bag and in the late seventeenth century by a silver casket, which by analogy was called a knottekistje. Three types occur, trunk-shaped, hexagonal and circular. The most common type is the trunk-shaped on four ball supports with domed cover and swing handle. Frisian marriage caskets are delicately engraved with symbolic scenes concerning love and marriage. Apart from Friesland, they were also made in West-Friesland, the most northern part of Holland.(see L. van den Bergh-Hoogterp, 'Trouw moet blinken', Cachet (1999) 2/3, pp. 10-13; A.L. Den Blaauwen, Nederlands Zilver 1580-1830, Den Haag, 1979, pp. 19, 372-373; B.W.G. Wttewaall, Klein Nederlands Zilver, Abcoude, 2003, pp. 314-315).