Complex sentence: The Vienna Landmark Commission saved it--after a campaign by Bernhard Leitner--and made it a national monument in 1971, and since 1975 it has housed the cultural department of the Bulgarian Embassy.
Split into simpler sentences: The Vienna Landmark Commission saved it--after a campaign by Bernhard Leitner--and made it a national monument in 1971. Since 1975 it has housed the cultural department of the Bulgarian Embassy.