Pepin

From the Foundation for Medieval Genealogy page on Carolingian Kings:

http://fmg.ac/Projects/MedLands/CAROLINGIANS.htm#_Toc240955191

King Pepin & his wife (Bertrada "au Grand Pied") had six children:

4. PEPIN (759-[761/62]). The Annales Laurissenses record the birth in 759 of "Pippinus regis filius" who was named after his father, specifying that he lived two years and died in his third year[43]. His birth and death two years later are recorded in the Royal Frankish Annals[44].

References:

[43] Annales Laurissenses 759, MGH SS I, p. 142.

[44] RFA 759, p. 43.

According to the Wikipedia page of his father, Pepin the Short:

http://en.wikipedia.org/wiki/Pepin_the_Short

Pepin died in infancy.