Makes the Themata Imperial Retinue spawn on wars they've started as well, will not spawn if the war is inside the Empire

Adds Senate
Senate Authority
Makes Crown Authority more expensive to increase
Increases wages of senators, and number of senators (5 per level)
Can be increased or decreased by decisions
Senate Faction
Desires greater powers of the senate, upon success will increase senate authority by 1 level, and implement Imperial Elective if it has been abolished
Themata are much less likely to join the faction if the emperor is able to dismiss them at will, basically never join at max crown authority (unless brave)
Senators
Increases your monthly prestige
Electors under Imperial Elective
Elected every 5 years, but if one dies or is removed will be replaced
Great Houses
10 max houses and house heads
House Influence
Every house member adds influence yearly, based off of number of titles in their realm
Can be spent to demand offices for relatives (costs 100 influence)
Can also be spent to make an office held by a house member hereditary (costs 250 influence)
House members are much more likely to vote for the house head in elections
Being a great house head also increases your vote score to non-house members as well

Gives king level themata royals courts
limited to the less luxurious amenities, still higher than barbarians though

Added tetrarchs, effectively a empire level viceroy. Requires you to own an empire other than your primary title, and a themata subject inside said empire. You create a tetrarch via a character interaction with said themata subject. Will always join wars you join, can be reintegrated upon the death of the tetrarch. Reintegration requires crown authority 4.

Reworked how themata are called to wars, any vassal, direct or indirect, and a count or higher, that borders the realm of the enemy will automatically be called to offensive and defensive wars. Offensive wars required the emperor to have either crown authority 3 or 4, defensive requires 2, 3, or 4. When one of the themata joins, they receive a temporary Imperial Retinue army that will disappear when the war is over. Counts get 100 heavy infantry and 50 heavy cavalry, doubling for each rank above, with king level themata getting 400 heavy infantry, and 200 heavy cavalry.

Makes a lot of background events into on_actions, in English this means there shouldn't be an occasional event popping up and immediately disappearing

Fixes imperial elective disappearing on succession

Changed up the Imperial Treasury event, and tweaked how salaries are paid out, gave AI automatic halved salaries so they don't go bankrupt in 5 seconds

Adds Imperial Prerogative cultural tradition, a generic social tradition that allows the adoption of imperial government, as well as some control growth and vassal opinion, requires the cultural head to have max crown authority, and be an emperor, and costs 10000 prestige to pass.

Updated to 1.6.*

Added Imperial Invasion CB for a kingdom level title, acts like tribal invasion, improved for Roman Empire

Gives development growth bonus to both Imperial government and Themata Government

Adds new options in Imperial Treasury Decision that allows to double or half the salaries of your themata subjects, doing so will affect your subjects' opinion of you (note, due to paradox math, the value may not actually be doubled or halved, but will be close)

Made revoking all titles of a theme makes all of their courtiers and the theme become your courtiers rather than disappearing into the aether.

Descriptor Fix 2: Electric Boogaloo
I can't actually tell if these work on my end, hopefully they do