Complex sentence: In Egypt he worked as a tobacco worker and came in contact with anarchists and anarchosyndicalists, mainly Greek and Italian immigrants, who during that period were very active among the tobacco workers of Alexandria and Cairo.
Split into simpler sentences: In Egypt he worked as a tobacco worker and came in contact with anarchists and Anarcho-syndicalists. These were mainly Greek and Italian immigrants, who during that period were very active among the tobacco workers of Alexandria and Cairo.