Here we are, arriving back in Napoli itself after our day trip to Capri. This is the Antemurale Thaon De Revel lighthouse with Il Vesuvio (Mt Vesuvius) in the background.
Antemurale translates to "in front of the wall". According to the Treccani dictionary, in maritime engineering it's "opera di difesa esterna di un porto, isolata dalle altre, che ripara l'imboccatura dalle onde del largo"; that is, works which are intended to defend the entrance of the port against the sea. That would be what the lighthouse is sitting on, rather than the lighthouse itself. The coastline runs pretty much north west from just south of Mt Vesuvius to the port of Napoli, where it curves around fairly abruptly to swing to the south west. The main port sits in the centre of that curve near the Castel Nuovo that we've seen before.
However there are a lot of cargo docks along the part of the coast before it swings around, some of which will be seen in other shots in this gallery. These form the Avamporto di Levante, literally the "outer port of the east". There is a breakwater which runs parallel to a lot of these docks, which protects them from the waters of the Gulf of Napoli.
At the northern end of the breakwater, it makes an abrupt 90 degree swing to the south west. This lighthouse sits on the end of that breakwater.
Another breakwater extends roughly east from just south of the main passenger port. When combined with the one that we see here, they provide a narrow, sheltered mouth for passenger vessels to pass into. Thus, the lighthouse does indeed sit on an "antemural"; the outer barrier (wall) which is protecting the harbour.
According to a dedicated page dealing with lighthouses, the tower is 12 metres (39 feet) tall. It sits on a stone base, which makes the focal plane (the distance between a line drawn straight out from the light, and the water) 18 metres (59'). It generates a green flash every 4 seconds.
As for the name, that's from Admiral Paolo Thaon di Revel. He was named chief of staff of the Regina Marina (the then-name of the Italian Navy) in 1913. He was the driving force in Italian naval operations from Italy's entrance to WW I in May 1915 until he resigned 5 months later because of disagreements with the minister of the navy. He bided his time as commander of the naval base in Venezia until he made a comeback at the start of February 1917.
Also in 1917 he was appointed to the Italian Senate... though he remained as chief of the Italian Naval Staff. These days that would be a significant conflict of interest. In those days... they did things differently. In 1922 King Vittorio Emanuele III anointed him as 1st Duca del Mare (1st Duke of the Sea).
He had a conflicted relationship with the Mussolini government. He was appointed as Minister of the Navy in 1922, but resigned in 1925. Because of anti-Fascist feelings, you ask? No, because of a turf war with the Chief of Staff of the Army. Nonetheless he was named as Grand Admiral in 1924. He became President of the Senate in 1943 after the fall of Mussolini.
He died in 1948 and was buried next to former army chief of staff Armando Diaz. I suspect that the post-mortem graveyard turf wars are still continuing to this day. Still, he has his name on this lighthouse all to himself.
