Conversation so far:
What was Ahmed Yassin's involvement in the attacks?
Ahmed Yassin was a founder of Hamas, an Islamist Palestinian paramilitary organization and political party. It has also claimed responsibility for a number of suicide attacks targeting Israeli civilians.
What did Ahmed Yassin do as leader of Hamas?
According to an Israeli government website, Ahmed Yassin was the dominant authority of Hamas leadership, which was directly involved in planning, orchestrating and launching terror attacks.
What else was said of Ahmed Yassin by the Israeli government besides him being the dominant authority of Hamas leadership??
In this capacity, Ahmed Yassin personally gave his approval for the launching of Qassam rockets against Israeli cities, as well as for the numerous Hamas terrorist bombings and suicide operations.
What was Ahmed Yassin's greatest accomplishment stated in the article about him?
The assassination of Ahmed Yassin led to Hamas, for the first time, being named the most popular movement in Palestine by the residents of the West Bank and Gaza Strip.

Question: What is the most important fact mentioned in this article?
Self-contained rewrite: What is the most important fact mentioned in the Ahmed Yassin article?