Khaled Meshaal moved into the top leadership position of Hamas in 2004, after its founder Sheik Yassin had been assassinated, on the orders of Israeli leader Ariel Sharon. Just a few days after that, Yassin's successor Abdel Aziz Al Rantissi was also killed. Meshaal had been in exile since the Arab-Israeli War of 1967. Meshaal was 31 when Hamas was founded in 1987. Yassin, within the Muslim Brotherhood, was a key proponent calling for the destruction of Israel and of setting up an Islamic state in all of ancestral Palestinian territory. He differed in this way from the head of the PLO, Yasser Arafat. Hamas had religious roots in social help and community-building - and was non-violent. But with the first Intifada uprising against Israeli domination the movement radicalised rapidly. One event in particular galvanised that. The Oslo Accord was signed in Washington in 1993 by Arafat and then Israeli Prime Minister Yitzhak Rabin, the first such Israeli-Palestinian peace agreement. Hamas still rejects Oslo and a right of existence for the state of Israel today. In the months that followed came the first Hamas suicide bomb attack, on a bus near a Jewish settlement in the West Bank. Seven Israeli soldiers were killed. Many more such bombings were to come. Yassin's death in 2004 marked another turning point. The change of direction entailed a different strategy in the movement, which was surging ahead politically. In legislative elections in January 2006, Hamas won the majority of votes from the Fatah movement. The national unity government that came out of this was short-lived. Factional conflict broke out in June 2007, a Palestinian mini-civil war which claimed more than 100 lives. This sealed the divisions between the two movements. Hamas seized control of the Gaza Strip and Fatah entrenched in the West Bank. In such limited territories already, the division weakened both. At last in March 2011, in massive demonstrations in Gaza and the West Bank, Palestinians called for an end to the fratricidal stalemate. A reconciliation was agreed in February 2012. Yet still a part of Hamas rejected this. The significance of Meshaal's historic homecoming to Gaza remains to be defined - whether it will lead to cooperation or continuing division.