I was recently looking up mills, and came across this fascinating picture of a Roman flour mill:

(Photo Credit: By Chris 73 (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons)

I’m so extremely used to the wheel type of mill that this almost shocked me. Just to be clear, I mean this kind of mill:

(Photo Credit: By Daniel Villafruela. (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons)

Interestingly, the wikipedia page called it an edge mill, and the wikipedia page for edge mills claims that edge mills were invented in China in the third century. Which, if true, means that the sort of mill stone I normally think of as a mill stone wouldn’t have existed at the time of Christ. Perhaps even more interesting, the sort of mill which quite possibly did exist then (the roman one in the first picture) looks to me far more complicated and advanced than the sort of flour mill which apparently superseded it. Very interesting.

The thing which led me to discover this was looking up Friedrich von Logau’s poem about the mills of God. The original poem is:

Gottes Mühlen mahlen langsam, mahlen aber trefflich klein,
ob aus Langmut er sich säumet, bringt mit Schärf ‘er alles ein.

Which was translated into English (according to Wikipedia, by Henry Wadsworth Longfellow) as:

Though the mills of God grind slowly; Yet they grind exceeding small;
Though with patience He stands waiting, With exactness grinds He all.