In modern plows both coulter and plowshare are detachable for easy replacement when worn or broken.
Triangular-shaped stone plowshares are found at the sites of Chinese Majiabang culture dated to 3500 BC around Lake Tai.
The British archaeologist David R. Harris says this indicates that more intensive cultivation in fixed, probably bunded, fields had developed by this time.
The ancient phrase from the biblical Book of Isaiah, "to turn swords to ploughshares," is still in common use today.
However, in classical antiquity during the Battle of Marathon, many Persians were slain by a deadly plowshare-wielding ally who appeared suddenly on the side of the ancient Athenians.