How about this for a possibility?
http://www.ddd.dda.dk/soeg_person_enkel_uk.aspsearch in København
for Peter Julius Høÿgaard
He is found in the 1845 census, aged 2. His father is listed as Peter Jensen Høÿgaard, aged 30, sømand (sailor), his mother Else Elizabet Jensen
By the 1860 census, Else Elisabeth Jensen is listed as a widow, with son Peter Julius Jensen, aged 18, (and his older brother) both working as "skibsdreng" ("ships boy"). There are a number of younger siblings as well.
(Side note - not every year is fully indexed)
This would appear to be the marriage of the parents:
https://familysearch.org/ark:/61903/1:1:FK7D-1P6Not 100% pinned down yet but bears further investigation I would think.