|In 88–119 AC
|In 134 AC, the Mountains of the Moon
In 132 AC, Princess Baela Targaryen claimed to have bedded Robert and a brother of his when a marriage was proposed between her and Lord Thaddeus. However, Archmaester Gyldayn notes the princess was deliberately provocative at times. Robert's father instead married Lady Floris Baratheon.
In 134 AC, a war of succession broke out in the Vale of Arryn after the death of Lady Jeyne Arryn, and the killing of the king's regent, Ser Corwyn Corbray, at Runestone. As the son of the Hand of the King, Robert was given command of an army of five thousand men. They set out on the kingsroad to the Bloody Gate to restore the King's Peace, as it was thought that the Mountains of the Moon would be passable with the coming of spring. Levies from Maidenpool, Darry, and Hayford joined them on the march, and six hundred Freys and a thousand Blackwoods joined them at the Trident, making them nine thousand strong entering the mountains. A naval attack was also launched at the command of Ser Gedmund Peake.
The high road proved far less open than had been assumed. Robert's host found itself struggling through deep snows in the mountain passes, slowing their advance to a crawl, and the baggage train was often attacked by mountain clans. Once, whilst looking for shelter, they roused the dragon Sheepstealer and saw Nettles. Robert was crushed by a falling boulder when the clansmen toppled half a mountainside down upon the column. Lord Benjicot Blackwood took charge of his host, and a third of the men had died by the time they reached the Bloody Gate.