"Heinrich" Karl Otto Hohenstaufen

-https://it.wikipedia.org/wiki/Enrico_Carlotto_di_Sicilia - ...Henry was appointed governor of Sicily and titular king of Jerusalem from 1250, but died at the age of fifteen and had no offspring.

-http://fmg.ac/Projects/MedLands/GERMANY,%20Kings.htm#MargaretaMAlbr...
6. KARL OTTO (Vercelli 18 Feb 1238-May 1254). The birth of an unnamed son is recorded by Matthew Paris in 1238[711]. Lord of Viterbo. Known as HEINRICH from 1242 or 1251. "Manfredus…imp. Frid. filius" accepted the allegiance of "Henricum…fratrem nostrum et Petrum Ruffum de Calabria regni Siciliæ marescalcum", on behalf of "regis…Conradi", by charter dated 15 Dec 1250[712]. "Henrico suo [=Friedrich] nepoti scilicet domini regis Angliæ" is recorded by Matthew Paris in 1251[713]. He was bequeathed the kingdom of Jerusalem and 10,000 uncias under his father's testament[714]. According to Matthew Paris, Pope Innocent IV unsuccessfully attempted to have Heinrich marry one his nieces, the chronicler specifying that Heinrich was virtually the Pope's adopted son[715]. Heinrich is named again in 1254 by Matthew Paris in relation to "opposition" to him in Sicily and Apulia[716]. Matthew Paris records the death in 1254 of "Henricus parvulus…filius Rom. imp. Frederici et imperatricis Isabellæ sororis regis Angliæ"[717].