The first timepiece in the F.P. Journe Souveraine collection was the Tourbillon Souverain made in 1999, as a series of 20 pieces under subscription. Each piece is numbered from one to 20. Francois-Paul Journe started his own manufacture in 1999, and this was the first piece to be signed Invenit et Fecit (invented and made by hand). Each of F.P.Journe’s pieces has been signed that way ever since. The Tourbillon Souverain has a remontoire-constant force device, which regulates the flow of energy, for optimal accuracy.