"historically valuable" is correct and usable in written English.
You can use it when referring to something that has significant value due to its association with important events or periods in history. For example: "This painting is historically valuable due to its proximity to the timeline of WWII."
This book is historically valuable, so they shouldn't change anything.
This monumental work of 17 volumes is historically valuable as a contemporary defense of Napoleon III.
These romantic, historically valuable and perfectly functioning gas street lights have been part of Berlin's cityscape for almost 200 years.
Patents that couldn't be restored were voided, and historically valuable models, like one of Robert Fulton's steamboat, were lost forever.
The tale's greatest tragedy may be that during each rebinding, margins were routinely sliced, eliminating historically valuable marginalia.
Official efforts are under way to digitise and restore landmark films, and to webcast historically valuable ones.
The initiative was carried out by the specially-formed Bureau of Military History 1913-1921 when it was realised that historically-valuable information was being lost as combatants and eyewitnesses grew old and died.
"They are very valuable historically".
"This is cutting edge science for historically and culturally valuable documents," said William Christens-Barry, a physicist at the Johns Hopkins School of Medicine.
Mr. Barquist said his work was "valuable historically because it proves that people on the frontier could afford luxury items like the sugar dish".
There is a full-size model of a blue whale's heart that youngsters can clamber through and a sample of ambergris, the whale waste that has historically been more valuable than gold because of its uses in perfumes and other fancy goods.
