This is the crown I designed and wore with my D&D rogue costume for Renaissance Faire.
It's a relatively fast print (mine took about 2 hours to print) with no supports needed.

• Make sure you print the crown with the spikes facing upwards.
  This allows the crown to print flat on the buildplate with no supports.

The inner-diameter of the crown is 19cm (about 7.5in), so adjust the XY-axis scale accordingly to fit your head size.

I included a test ring ("Test_ring_for_crown.stl") so that you can experiment with various scales without wasting filament.