On this day (13th January) in AD 101, Lucius Aelius Caesar, Hadrian’s first intended successor, was born. Aelius, whose birth name was Lucius Ceionius Commodus, came from a powerful senatorial family (the gens Ceionia). His father was consul in 106, and his paternal grandfather was consul in 78. Aelius also served as consul in 136 and was officially adopted by Hadrian in the course of the same year. Lucius Ceionius Commodus was thereafter named Lucius Aelius Caesar, a title that marked him as heir to the throne. Hadrian spent four hundred million sesterces on celebrating the adoption with gifts to the people and soldiers, as well as putting on lavish games in the Circus Maximus.

However, Aelius never attained the throne. He died of tuberculosis a few months before Hadrian on 1st January 138. Hadrian was, therefore, forced to choose a new heir, Antoninus Pius.

“He was a man of joyous life and well versed in letters, and he was endeared to Hadrian, as the malicious say, rather by his beauty than by his character.” Historia Augusta

“He was considerate of his family, well-dressed, elegant in appearance, a man of regal beauty, with a countenance that commanded respect, a speaker of unusual eloquence, deft at writing verse, and, moreover, not altogether a failure in public life.” Historia Augusta

“[…] in the province to which he had been appointed he was by no means a failure;  for he carried on a campaign with success, or rather, with good fortune, and achieved the reputation, if not of a pre-eminent, at least of an average, commander..” Historia Augusta

“Hadrian gave orders that colossal statues of Verus should be set up all over the world, and in some cities he even had temples built.” Historia Augusta

2020 update: 

An unnoticed portrait of Hadrian’s first heir, L. Aelius Caesar, in Rome’s Casino Aurora?