This sentence in Orberg’s LLPSI has been a bit tricky. Livy is describing Taquin the Proud’s style of governing.
Hic enim regum primus traditum a prioribus morem de omnibus rebus senatum consulendi solvit, domesticis consiliis rem publicam administravit, bellum, pacem, foedera, societates per se ipse, cum quibus voluit, iniussu populi ac senatus, fecit rupitque.
It’s very hard to work out what "Hic enim regum primus..’ means - This first of kings? - though he was the last of the kings!? Also the word order seems to resemble what you’d find in poetry rather than in prose. The only way I can attempt to translate it (just to confirm its meaning - I’d rather not translate) is to assume that this is somewhat idiomatic Latin. Words in square brackets are not in the text but are assumed (by me) to be the meaning…
[In these circumstances he was] the first of the kings [who] broke the traditional custom, from the earliest [times], of consulting the senate concerning all things, he governed for private interest - war, peace, treaties, allies according to his own wish, [and] with whom he wished, without the sanction of the people or the senate, he made and broke.
I think that domesticis consiliis is an ablative of manner and should be translated as “with private counsel” or something to that effect. Other than that, your translation seems fine.
There’s nothing poetical about the Latin.
primus hoc feci I first did this i.e. I was the first to do this. So here He was the first to break with tradition.
As distinct from
primum hoc feci I first did this (then I did something else).
Hic enim regum primus traditum a prioribus morem de omnibus rebus senatum consulendi solvit, domesticis consiliis rem publicam administravit, bellum, pacem, foedera, societates per se ipse, cum quibus voluit, iniussu populi ac senatus, fecit rupitque.
traditum a prioribus morem - custom handed down by? / from? the ancestors?