By A.D. 1200, Chinese and European sailors used magnetic compasses to steer their ships.
(Chinese and European sailors; used; magnetic compasses; to steer their ships) Context(Chinese and European sailors used,List([14, 47))):(Chinese and European sailors; used magnetic compasses to steer; their ships)
Chinese and European sailors used,List([14, 47))
Chinese and European sailors Chinese and European sailors
used used magnetic compasses to steer
magnetic compasses to steer their ships
their ships