Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Frontiers of the Roman Empire' has mentioned 'Wood' in the following places:
Occurrence Sentence Text Source
The initially simple wood and earth structures were systematically converted under Emperor Hadrian into stone encampments.
The initial wood and earth structures, were systematically converted under Emperor Hadrian into stone barracks and, in the 4th century, redesigned and massively strengthened in order to match new strategic requirements.