Complex sentence: In Aehrenthal's Hungarian noble half, Hungary an equally strong threat to the loss of its historic Slavic provinces should Pan-Slav take root; equally threaten its military security and economic future.
Split into simpler sentences: In Aehrenthal's Hungarian noble half, Hungary saw an equally strong threat to the loss of its historic Slavic provinces should Pan-Slav take root. It would equally threaten its military security and economic future.