Irish history is marked by its early Celtic culture, which began around 600 BC. The arrival of Christianity in the 5th century, led by figures like Saint Patrick, significantly influenced Irish society. Over the centuries, Ireland faced invasions and settlements by the Vikings and later the Normans, which shaped its political landscape. In the 17th century, English rule intensified, leading to conflicts such as the Irish War of Independence in the early 20th century. This struggle resulted in the partition of Ireland in 1921, creating Northern Ireland and the Irish Free State, which later became the Republic of Ireland.