I understand that from Claudius’ ascension you could argue that is the key point due to the praetorian guard acclaiming him princeps, however under Nero he still attempts to gain the Senate’s support so I am wondering what exactly is the defining point for the senate’s loss of power? My question is less on the actual fact of when the senate actually lost power but rather when they actually understood they no longer had power. Thanks for any replies
This may not serve to answer your question, but, after having recently read a thought-provoking book focused on the Senate’s increased use of the so-called senatus consultum ultimum as it struggled to maintain power during the late Republic (essentially covering from Tiberius Gracchus to about 49 BC), I believe the Senate was quite cognizant of how its power was diminishing as individual military leaders garnered and concentrated power. Its argument for resorting to this instrument, salus populi suprema lex esto, is hardly convincing, especially since in this quotation the populace seems to be the senators, not the plebs, as almost every recorded usage of this tool by senators was to stop measures which would ultimately benefit the populace.
As to why they did not simply give in to these new circumstances, it might come down to a mentality question. The Senate, for the senators at least, represented a clear way of ordering society, led by their ancestors, with genealogy playing a vital role in Roman society, and the lack of senatorial ancestry (homus novus) was pretty much what marked Cicero since the start of his career.
Summing up, I believe it is a question of identity. PM if you want to talk more because I find Roman history interesting.
The book I read was Videant consules: las medidas de excepción en la crisis de la república romana by the Spanish historian Antonio Duplá Ansuátegui (not 100% sure if there is an English translation of the work).