A few more Gloranthan timescale observations
The Opening of the Seas is as far away from 1621 as the resignation of Richard Nixon is from our own time.
The foundation of the Lunar Empire is about as far away from 1621 as the Thirty Years War is from our own time.
The apotheosis of Sartar is about as far away from 1621 as the start of the First World War is from our own time. The foundation of Sartar is about as far away from 1621 as the death of Wild Bill Hickok is from our own time.