The First Triumvirate was by no means an official deal but
more of a private pact if you will. In fact, Julius Caesar was eager
to get
Marcus Tullius Cicero on board but Cicero turned down the
offer because he thought this type of informal agreement between
political leaders was unconstitutional.
Ironically, Cicero became the victim of the Second Triumvirate.
The Second Triumvirate was officially
called Tresviri rei publicae constituendae, which means that
the officials in question had been formally appointed to the task of
organizing the state.
And so they did, some with more success
than others:
Marcus Aemilius Lepidus was deserted by his soldiers and forced to
retire in 36 BC, Mark Antony killed himself in 30 BC, and Octavian
became Augustus Caesar, the first Roman Emperor, in 27 BC.