In January 1227, an army of the Livonian Brothers of the Sword with Letts, Germans of Riga and native Livonians (20,000 men commanded by William of Modena) crossed on sea ice from the mainland and attacked the island of Saaremaa to reduce the last holdout of pagan Estonians. The Estonians surrendered on Muhu at a circular stronghold called Mona, the earthworks of which are still preserved near the causeway between the islands. This ended the Estonian Crusade.
Muhu is also famous for having the only still-working windmills in the whole country of Estonia, and for the Battle of Moon Sound in September-October 1917 between Russian and German naval forces (and three daring British submarines)
