Complex sentence: Isaac Brown, a carpenter and trader with Native Americans, reportedly grew fearful of attacks from the natives in 1856, so he built an Orson Fowler-designed eight-sided house which was designed for hiding.
Split into simpler sentences: Isaac Brown, a carpenter and trader with Native Americans, grew fearful of attacks from the natives in 1856. So he built an Orson Fowler-designed eight-sided house which was designed for hiding.