Answer:
The adverb phrase is "In the summer of 1793", which modifies the verbs 'were tried' and 'executed'.
Step-by-step explanation:
Adjective phrase is the accessory term in a sentence that has adverbial value and indicates some circumstance of the fact expressed by the verb, or intensifies the sense of it, of an adjective or an adverb.
Because it has an adverbial value, the adverb phrase also presents semantic classifications according to the idea it represents in relation to the term with which it relates.