Complex sentence: When difficulties occurred in its construction, Gallier was called in to revise the foundations and Dakin lost the contract in 1839; ever afterward Gallier erroneously claimed it as one of his buildings.
Split into simpler sentences: When difficulties occurred in its construction, Gallier was called in to revise the foundations and Dakin lost the contract in 1839. Ever afterward Gallier erroneously claimed it as one of his buildings.