The Queen became the first British monarch to set foot on the Republic of Ireland in 100 years.

Queen Elizabeth II is on historic four-day trip. BBC reported that the Queen's arrival ensued one of the biggest security operations ever taken up in Ireland.

The momentous event comes after a gap of 100 years since the Queen's grandfather King George V arrived in Dublin in July 1911.

Boston reported that the Queen's arrival underscores the strong Anglo-Irish relations after the success of Northern Ireland peacemaking which followed a bloody three-decade-conflict which left 3,700 dead.

Here are the photos of the historical event: