History Vertical axis windmills The first practical windmills were the vertical axle windmills invented in eastern LOCATION@1 , as recorded by the MISC@1 geographer PERSON@1 in the 9th century .

Vertical axle windmills were used in eastern LOCATION@1 -LRB- LOCATION@2 -RRB- by the 9th century AD as described by Muslim geographers .
