Complex sentence: One of his first commercial clients was Harry Mittleman, who constructed several apartment buildings from designs provided by Feig, including Blackstone Apartments, an Egyptian Revival structure cited as a key example of Feig's work.
Split into simpler sentences: One of his first commercial clients was Harry Mittleman, who constructed several apartment buildings from designs provided by Feig, including Blackstone Apartments. Blackstone is an Egyptian Revival structure cited as a key example of Feig's work.