SCHIAVONA, Napoleonic period (?) FERDINAND IV of Two Sicilies

[Jim McDougall]

This schiavona is inscribed VIVA FERDINANDO IV OF THE TWO SICILIES (Naples and Sicily) and I am hoping to get some clarification on proper period.
Ferdinand I (1951-1825) reigned as Ferdinand IV from 1759 as King of Naples and Sicily ....but in the complex chaos of monarchies in these times and which principalities were ruled by whom, what name and number etc. are hard to figure out.

With French Napoleonic invasions in Italy 1790s, occupation of Rome, then invasion of Naples, Ferdinand fled to Sicily.
He was restored to the throne of Two Sicilies in 1816 at end of Napoleonic wars and died 1825, so terminus ante quem for the blade in that year.

Has anyone else seen or acquired items from Ferdinand IV of the Two Sicilies? and might shed some light on possible date on this blade and the traditional schiavona hilt it is mounted in.

The grip was professionally restored at the time I got the sword over 25 years ago.