Sentence:  Indentured service continued through the 18th and into the 19th century. In fact there was not appreciable decline in the number of German “<WSD>free-willers</WSD>” who entered Maryland until after 1817, when legislation protecting the servants made the trade unprofitable for the shipmasters. 
Meaning of the word marked with <WSD> tags:  An immigrant to the United States who, upon arrival, voluntarily became an indentured servant.