The siege began on April 19 after the Battles of Lexington and Concord, when the militia from surrounding Massachusetts communities blocked land access to Boston. The Continental Congress formed the Continental Army from the militia, with George Washington as its Commander in Chief.
The use of women, children and immigrant allowed industrialists and factory owners to keep wages low for native born men. This was an important catalyst for the organization of labor unions, Children often worked long hours for low pay. The same was true of women and immigrants.
