expression, adverb
so ... that ...; to that extent; to that degree
Fixed adverbial phrase used to emphasize the degree or extent of a preceding statement, often in the pattern 「AことほどBように」 meaning 'B to the extent that A'. It is somewhat literary and formal, but can appear in emphatic speech.
彼の話は面白いことほど左様に、皆が聞き入っていた。
His story was so interesting that everyone was listening intently.
その景色は美しいことほどさように、言葉を失った。
The scenery was so beautiful that I was at a loss for words.