Conversation so far:
What does Silent Sentinels refer to?
The name Silent Sentinels was given to the women because of their silent protesting.
What is a Silent Sentinel?
The Silent Sentinels were a group of women in favor of women's suffrage organized by Alice Paul and the National Woman's Party.
Were the Silent Sentinels protesting for womens rights?
They protested in front of the White House during Woodrow Wilson's presidency. The protesters served as a constant reminder to Wilson of his lack of support for suffrage.

Question: What year was this?
Self-contained rewrite: What year did the Silent Sentinels start protesting?