Marcus, now effectively sole ruler of the Empire, makes some show of resistance: the biographer writes that he was "compelled" to take imperial power.
This may have been a genuine horror imperii, "fear of imperial power".
With his preference for the philosophic life, Marcus finds the imperial office unappealing.
His training as a Stoic, however, has made the choice clear: it is his duty.
Although Marcus shows no personal affection for Hadrian (significantly, he does not thank him in the first book of his Meditations), he presumably believes it his duty to enact the man's succession plans.
Thus, although the senate plans to confirm Marcus alone, he refuses to take office unless Lucius receives equal powers, despite the fact that Verus is obviously less competent to rule.
The senate accepts, granting Lucius the imperium, the tribunician power, and the name Augustus.
He is soon formally elected as Pontifex Maximus, chief priest of the official cults.
Marcus becomes, in official titulature, Imperator Caesar Marcus Aurelius Antoninus Augustus; Lucius, forgoing his name Commodus and taking Marcus' family name, Verus, becomes Imperator Caesar Lucius Aurelius Verus Augustus.
It is the first time that Rome is ruled by two emperors.
In spite of their nominal equality, Marcus holds more auctoritas, or "authority", than Lucius.
He has been consul once more than Lucius, he had shared in Pius' administration, and he alone is Pontifex Maximus.
It would have been clear to the public which emperor was the more senior.
Immediately after their senate confirmation, the emperors proceed to the Castra Praetoria, the camp of the praetorian guard.
Lucius addresses the assembled troops, which then acclaim the pair as imperatores.
Then, like every new emperor since Claudius, Lucius promises the troops a special donative.
This donative, however, is twice the size of those past: twenty thousand sesterces (five thousand denarii) per capita, with more to officers.
In return for this bounty, equivalent to several years' pay, the troops swear an oath to protect the emperors.
The ceremony is perhaps not entirely necessary, given that Marcus' accession had been peaceful and unopposed, but it is good insurance against later military troubles.
Upon his accession he also devalues the Roman currency, decreasing the silver purity of the denarius from 83.5% to 79%—the silver weight dropping from 2.68 grams to 2.57 grams.
However, Marcus will later revisit the issue of currency reform.
If Pius' funeral followed the pattern of past funerals, his body would have been incinerated on a pyre at the Campus Martius, while his spirit would rise to the gods' home in the heavens.
Marcus and Lucius nominate their father for deification.
In contrast to their behavior during Pius' campaign to deify Hadrian, the senate does not oppose the emperors' wishes.
A flamen, or cultic priest, is appointed to minister the cult of the deified Pius, now Divus Antoninus.
Pius' remains are laid to rest in the Hadrian's mausoleum, beside the remains of Marcus' children and of Hadrian himself.
The temple he had dedicated to his wife, Diva Faustina, becomes the Temple of Antoninus and Faustina; it survives as the church of San Lorenzo in Miranda.
