One side managed, just about at times, to keep a lid on a motley crew of protestors.
This protest was organised by Éirígí, a republican political party, which had its own “stewards” to control things.
They were on the bottom left corner of Parnell Square, on the junction of Parnell Street and Parnell Square West.
On the top right corner, on North Frederick Street, more extreme elements were gathered. This protest was organised by Republican Sinn Féin, close to the Continuity IRA, and the 32 County Sovereignty Committee, close to the Real IRA.
About 45 members gathered near the Garden of Remembrance on Parnell Square East, where Queen Elizabeth was due to arrive to place a wreath.
They began to throw rocks, bricks and bottles at uniformed and unprotected gardaí at the barricade.
A garda public order unit, on standby nearby, moved in and the crowd was pushed back up onto Dorset Street.
The protesters were joined by onlookers and up to 100 people began attacking gardaí. They lit wheelie bins and pushed them towards gardaí, while others threw bricks and other missiles, including lit fireworks.
The riot squad pushed them down Dorset Street and Blessington Street, where a number grabbed barricades and tried to throw them at gardaí. Many of them lit rubbish bags as they ran away.
Gardaí arrested 21 people for public order offences. Twenty are expected at Cloverhill District Court charged with public order offences. One was released without charge having received an adult caution at Pearse Street Garda Station.
Meanwhile, back at the Éirígí protest, numbers had swelled from about 100 to roughly 200.
About 30 of them had started a protest at 1pm when they gathered at the Spire on O’Connell Street. They chanted and beat bodhráns while some of the protesters set fire to a British flag.
They were surrounded by gardaí. A larger group tried to join the protests from Henry Street but were prevented by gardaí who forced them back.
The group at the Spire voluntarily left and joined their colleagues and headed to nearby Moore Street for a rally.
Éirígí Dublin City Councillor Louise Minihan laid a wreath at the last 1916 headquarters on Moore Street, before leading the rally up to Parnell Square.
This protest was always going to be a bit different from the other one.
Éirígí chairman Brian Leeson told protestors this was a sit-down protest, albeit a loud one.
Chants of “whose streets, our streets” and “they say bow down, we say rise up” filled the air, joined by whistles, drums and shouting.
Mr Leeson, together with organisers and up to 10 stewards, tried to keep everyone under control.
While roughly half of the crowd appeared to be Éirígí supporters, the remaining half looked like the typical element these protests sometimes attract.
At one stage one of the stewards was overheard referring to the number of “scumbags” present.
Many of them had the characteristic bottles of Coca-Cola and 7-Up filled with booze, while a few others were openly smoking joints.
They were joined by a small group of children, aged 10 to 13, who got involved in the chanting.
Some of the protesters were holding aloft a bizarre banner with drawings of a banker, the pope, the symbol of the IMF, and the queen suggesting they should all be guillotined.
The two hours of protest were filled with speeches, chanting, whistling, banging and rebel songs, which half the crowd could sing and the others couldn’t.
Repeatedly, when there were any signs of control loosening, Mr Leeson and the stewards got people to sit down.
This even happened when some of the crowd tried to stand up and sing the national anthem.
There were occasions when the stewards appeared to remove some protestors.
There was only one brief moment, at 3.30pm, that the tension got edgy and a solitary wooden pole was thrown into the air towards gardaí manning the barricades. This was followed by a couple of plastic bottles which landed harmlessly.
Mr Leeson could be seen remonstrating with a number of protestors while stewards returned some control.
Mr Leeson urged the crowd to “keep their powder dry” for a larger protest this evening, which he hoped would attract thousands.
There were a number of bomb scares during the day, including three at courthouses in Drogheda, Dundalk and Monaghan, and one in Fairview and Summerhill in Dublin.