Sentence:  In spite of the importance of this route it remained until a few years ago very insecure. Overhung almost its entire length by the inaccessible fastnesses of Lololand, the passing caravans dared journey only with convoy, and even then were frequently overwhelmed by raiders from the hills, who carried off both trader and goods into the mountains, the former to lifelong <WSD>servitude</WSD>. 
Meaning of the word marked with <WSD> tags:  The state of being a slave; slavery.