Daesh, which is also known  as Islamic State in Iraq and Syria (ISIS) and in  2014, the Islamic State, is the Sunni insurgent group that primarily operates in western Iraq and eastern Syria. It emerged under the name ISIL in April 2013 and launched an offensive in early 2014 that pushed Iraqi government forces out of key western cities. 

In Syria, it fought against both government forces and rebel factions in the Syrian Civil War.Some affiliates with weak connections to ISIL leadership, notably Islamic State–Khorasan Province IS also known as ISIS-K remained active elsewhere. 

History And Rise Of ISIS  

The Islamic State of Iraq and the Levant (ISIL) traces its roots back to the Iraq War, which lasted from 2003 to 2011. During this time, Al-Qaeda in Iraq (AQI) emerged as a key player in the Sunni insurgency against the Iraqi government and foreign occupying forces. AQI, led by Abu Musab al-Zarqawi, was responsible for many brutal attacks during the conflict. Following Zarqawi's death in 2006, the group merged with several smaller militant groups and rebranded itself as the Islamic State of Iraq (ISI).

The sectarian nature of Iraqi politics at the time, particularly the repression of Sunnis by Prime Minister Nouri al-Maliki's administration under the guise of fighting AQI. The withdrawal of foreign troops and the sharpening of Sunni discontent allowed AQI/ISI to make a comeback from 2011, and bombings by Sunni militants became frequent once again.  

Expansion And Declaration Of ISIS  

ISIS  extended its influence from its base in Al-Raqqah by launching successful attacks in Syria and Iraq. After Iraqi government forces tried to quell protests in predominantly Sunni cities like Fallujah and Al-Ramadi  ISIS fought back with local militias and took control of those cities in January 2014. This capture proved to be a propaganda victory for ISIL, which flaunted its "liberation" of those cities to the aggrieved Sunnis in western Iraq. The group then proceeded to move north and took Mosul, Iraq's second-largest city, without resistance in June. 

Calls for international intervention grew, and on August 8, the United States launched airstrikes in Iraq to prevent ISIL from advancing into the autonomous Kurdish region. Although the strikes halted ISIL's advance, they did not dislodge the group from its entrenched position in Iraqi territory. ISIL continued to produce graphic and provocative propaganda. In August and September, the group released a series of videos showing ISIL fighters beheading Western journalists and an aid worker in retaliation for the US airstrikes. 

Links And Attack On Abroad  

Confronted with setbacks in its primary territories in 2015, ISIS shifted its attention to utilising global networks of extremists to execute attacks worldwide. On November 12, two suicide bombers targeted a Shiʿi neighborhood in Beirut, causing the deaths of over 40 individuals in retaliation for the militant group Hezbollah's intervention against ISIS in Syria. The following day, eight terrorists associated with ISIS launched a series of coordinated gun and bomb assaults in Paris, resulting in the deaths of at least 130 people at various locations throughout the city. 

ISIS representatives claimed responsibility for the attacks as vengeance for France's participation in the international military campaign against ISIS. In the ensuing months, an array of ISIS-related attacks occurred across the world. In some instances, such as the bombing at Brussels Airport in March 2016, authorities were able to confirm that there was operational coordination between the perpetrators and ISIS commanders. 

In other cases, however, such as two shooting sprees in the United States - in San Bernardino, California, in November 2015 and in Orlando, Florida, in June 2016 - the attackers pledged allegiance to ISIS but did not seem to have been in contact with its leadership structure. Such assaults, frequently referred to as "homegrown" or "lone-wolf" attacks in the media, had been expressly encouraged by ISIS in its propaganda as a means of spreading violence beyond the scope of its extremist networks.  

Conclusion And Decline  

Around mid-2015, it seemed that ISIL was beginning to weaken due to its simultaneous battles with Kurdish troops and their Western supporters, Syrian government forces, and Iraqi forces. Kurdish soldiers gradually solidified their control over the regions bordering Turkey in northern Syria, and by early 2016, they had come close to capturing Al-Raqqah. In Iraq, government forces gradually regained lost ground and retook important cities such as Al-Ramādī in December 2015 and Fallujah in July 2016. In the meantime, an intensifying U.S.led air campaign weakened ISIL's grasp on crucial strongholds, allowing local forces to recover.

 On July 9, 2017, Iraqi Prime Minister Haider al-Abadi announced that Iraqi forces had fully retaken Mosul, the largest city under ISIL's control. In October, the Kurdish Syrian Democratic Forces (SDF) declared victory in Al-Raqqah, which used to be ISIL's capital. Meanwhile, Assad's forces continued to put pressure on ISIL, pushing them out of Dayr al-Zawr in November 2017. Later that same month, both the Syrian and Iraqi governments declared ISIS defeated, although the group still held a small amount of territory on the outskirts of Iraq and Syria.