The burial of Michael Collins took place on August 28th 1922. It was the largest and most sombre of that era.
From City Hall, Collins’s remains were taken to the Pro-Cathedral through streets thronged with thousands of mourning spectators, some occupying the windows of the buildings overlooking the street. Read more: https://www.rte.ie/centuryireland/index.php/articles/funeral-procession-for-michael-collins-one-of-the-largest-ever-witnessed-in-dublin
Tens of thousands people lined the route to Glasnevin Cemetery to pay tribute to Collins, as his cortêge made its ways through the city. It is said that 20,000 soldiers and civilians marched behind the coffin. The oration was given by General Richard Mulcahy before he was laid to rest among good and the great of who played their part in the course of Irish freedom.
Sources
Weekly Freeman’s Journal 02 September 1922