“The Assad regime cannot slaughter its way to legitimacy,” President Obama said at the height of eastern Aleppo’s bombardment a few weeks ago, during his last press conference of 2016.

But that’s precisely what the Syrian president and his allied forces did in the battle for Aleppo and throughout much of the nearly six-year Syrian civil war, with incessant and indiscriminate bombings and “medieval” siege tactics. The brutal approach required a consistent and blatant disregard for human rights and international law, and the countless warnings from the international community, the U.N., Human Rights Watch, Amnesty International, and over 200 other human rights groups and NGOs.

Assad and ally Russia dismissed dire diplomatic warnings and independent reports as “unfair and dishonest,” “hoaxes” and “propaganda,” and regularly pointed to crimes committed by opposition rebel groups during the battle. But the U.N.’s High Commissioner for Human Rights noted that Assad’s allied forces were “responsible for the overwhelming majority of civilian casualties” in Aleppo.

“The Assad playbook now is that you can crush your people; you can destroy cities; you can attack with chemical weapons; you can enable extremists — and the international community will stand by and not do anything,” resident fellow Hassan Hassan, of the Tahrir Institute for Middle East Policy, told the New York Times earlier this month.

Bashar Assad is now starting to wear his newfound inevitability, recently taking some time away from his various battlefronts to pose for some cynical, well-crafted holiday photos. And as he reintroduces himself to the world as Syria’s immovable object — with help from allies Russia and Iran, who with Turkey have organized a cease-fire while they undertake broader peace negotiations — it’s worth taking a look back at the many dire international warnings during the final months of the battle for Aleppo that were either rejected or ignored on the way to this once unthinkable outcome.

— Muskilda Zancada, Head of Mission for Syria at Médecins Sans Frontières, condemned the continued fighting in Aleppo and warned of an “upsurge in attacks targeting civilian infrastructure, including affecting hospitals.”

Later the same month, The New Yorker’s Ben Taub chronicled Assad’s calculated and bloody war on Syria’s doctors, and the volunteers attempting to provide emergency medical aid.

— U.N. aid chief Stephen O’Brien warned that critical aid and supplies were running dangerously low and required immediate action in eastern Aleppo. “This is no hollow warning,” O’Brien added. “This is highly likely to occur again unless you enforce access.” O’Brien would make many similar warnings before the Security Council in the months to come.

— HRW’s Nadim Houry warned the international community as Assad’s forces tightened their siege in late July.

— Omran, the 5-year-old boy pictured caked in blood and dust while awaiting medical attention briefly returned the world’s attention to the civilian suffering taking place inside eastern Aleppo. When confronted with Omran’s image months later, Assad deflected and called it “a forged picture.”

— HRW’s arms director Steve Goose urged international action on the issue after the monitoring group documented at least 18 instances, over a stretch of nine weeks, where the Syrian government, in violation of international laws, used incendiary weapons in airstrikes on civilian areas of rebel-held eastern Aleppo and Idlib.

— U.N. special envoy Staffan de Mistura responding to reporters after the U.N. announced it would launch an investigation into the Syrian government’s use of chemical weapons in Aleppo. The investigation came soon after reports from doctors and independent monitoring groups cited evidence of a “chlorine attack” on rebel-held territory.

—Amnesty International’s Magdalena Mughrabi warned of war crimes. A doctor who spoke to the human rights group described the smell of chlorine on victims’ clothing, and reported children struggling to breath.

The chemical attacks came nearly three years after Assad’s government agreed to the Chemical Weapons Convention and vowed to rid the country of its robust supply of chemical weapons. Assad’s forces have regularly been accused of using chlorine as a weapon since the 2013 agreement.

— UNICEF Deputy Executive Director Justin Forsyth slammed government forces and reported that 96 children had died and 223 more were injured in eastern Aleppo a few short days after a U.S.-Russia cease-fire faltered.

— U.N. Secretary-General Ban Ki-moon said in an unusually frank response to continued reports of indiscriminate bombings and allegations of war crimes in the besieged Syrian city. Secretary Ban urged the Security Council to take immediate steps to insure the protection of civilians, hospitals medical professionals, and humanitarians.

— U.K. Ambassador Matthew Rycroft said before walking out of a September U.N. Security Council meeting with fellow U.S. and French ambassadors in protest. The three accused Russia and Assad’s forces of committing war crimes.

— Jean-Marc Ayrault, France’s foreign affairs minister, warned as he attempted to orchestrate a cease-fire resolution in late September, as U.S.-Russia-brokered peace talks stalled.

— Carlos Francisco, MSF’s head of mission in Syria, warned, “The few remaining doctors with capability to save lives are also confronting death.” The group reported that 23 hospitals had been attacked in eastern Aleppo since July. MSF would go on to report continued attacks on its facilities, including a children’s hospital, during the siege.

— Secretary of State John Kerry accused Russia and Assad’s forces of regularly bombing hospitals and medical facilities, and called for a war crimes investigation shortly after U.S.-Russia-brokered cease-fire negotiations fell apart in early October.

—U.N. humanitarian chief Stephen O’Brien in one of his many dire warnings to a paralyzed Security Council regarding the deteriorating situation in Aleppo.

— UNICEF executive director Anthony Lake decried the bombing of children at a school in Idlib province near Aleppo. “This is a tragedy. It is an outrage. And if deliberate, it is a war crime,” Lake said.

— U.N. High Commissioner for Human Rights Zeid Ra’ad al-Hussein strongly condemned Assad and Russia’s constant and indiscriminate bombing of eastern Aleppo, describing their actions as “crimes of historic proportions,” that had transformed the city into a “slaughterhouse.”

— Stephen O’Brien once again found himself pleading for action from the international community after Russia and China blocked yet another U.N. Security Council resolution designed to alleviate Aleppo’s woes.

—Amnesty International’s Samah Hadid decried the continued actions of Syrian government forces in eastern Aleppo. The rights group warned of greater potential violations from Assad’s forces as they began to win back large swathes of territory. “Given the Syrian government’s long and dark history of arbitrary detention and enforced disappearances on a mass scale, it is even more crucial that civilians are protected in newly captured areas of Aleppo city.”

— The U.N.’s humanitarian spokesperson Jens Laerke described reports that his organization had received of civilians being shot on the streets and in their homes as Assad’s forces closed in on the last shreds of rebel-held eastern Aleppo.

— The U.N.’s High Commissioner Zeid Ra’ad Al Hussein responded to the numerous “credible” reports his organization had received in the final days of the battle for Aleppo.

— U.S. Ambassador to the United Nations Samantha Power asked of her Russian, Syrian, and Iranian counterparts during an emergency Security Council session at the U.N. in December.

— Outgoing U.N. Secretary General Ban Ki-Moon said the international community “had failed the people of Syria. Peace will only prevail when it is accompanied by compassion, justice, and accountability for the abominable crimes we have seen. ”

— U.N. Ambassador Christian Wenaweser said before her General Assembly colleagues voted through a resolution on December 21 that establishes a team to document and collect evidence of war crimes and rights abuses perpetrated throughout Syria’s civil war.