Complex sentence: Although the facility had been ravaged by disastrous fires on several occasions (the current architecture dates back to 1877), the two buildings of the facility were originally built in the 7th and 17th centuries.
Split into simpler sentences: Although the facility had been ravaged by disastrous fires on several occasions (the current architecture dates back to 1877). The two buildings of the facility were originally built in the 7th and 17th centuries.