The rijksdaalder was an 18th century Dutch coin worth 2½ gulden or 50 stuiver.
Following decimalization (in 1816), 2½-gulden coins were no longer produced because a 3-gulden coin was thought to better fit in the series of denominations. This turned out to be a mistake (due to the high silver price) and from 1840 onward 2½-gulden coins were produced again. Production stopped in 2002 due to the introduction of the euro. 2½-gulden coins were better known by their nickname rijksdaalder, daalder or knaak.
The Royal Dutch Mint still mints a silver ducat today.
The similarly named Reichsthaler, rixdollar, riksdaler and rigsdaler were used in Germany and Austria-Hungary, Ceylon (Sri Lanka), Sweden, Denmark, and Norway, respectively.