Twin 13-month-old boys conjoined at the head were successfully separated early Friday at the Children's Hospital at Montefiore Medical Center in the Bronx, CNN reported.

On Thursday, their parents began a long vigil as surgeons in New York began the operation.

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Nicole and Christian McDonald say their sons have distinct personalities. Jadon is rowdy while Anias, who had to fight harder to live in the early months of his life, is more contemplative.

McDonald's photos usually show just one of her sons at a time.

"My pictures will always depict my boys as separate because that's what they are to me. Their faces are so beautiful. I would hate for people to get caught up in the bridge between them," Nicole wrote on the family's GoFundMe page.

Doctors have been preparing the boys for this day since the boys were born last year, according to CNN. They already have undergone three operations to start the long process. Doctors placed four tissue expanders in their heads to make the separation process a little easier.

At 7:15 a.m. Thursday, Anias and Jadon were wheeled into the operating room where the 20-hour surgery is taking place. Their parents and 3-year-old big brother Aza kissed them before saying goodbye, hoping they will see the twins again healthy and separated soon.

Early Friday, Nicole posted on her Facebook page that the surgery was "a go," and that "By morning ... There will be two babies in two beds."

Goodrich informed the family of the separation around 3 a.m. "Well, we did it," Goodrich said.  "But we are definitely not out of the woods by any means," Nicole wrote on her Facebook page.

An 8:18 a.m. Facebook post from Nicole McDonald said that Jadon was out of surgery.

By 10:19 a.m., Friday Nicole McDonald said on Facebook that Anias was still in surgery and that doctors had to reopen his incision.

McDonald posted that Anias was out of surgery at 2:30 p.m.

"Thirty hours away from you was too long," she wrote "And almost five  hours away from your brother!! You look so small in that big bed all by yourself. I know things got pretty hard and that you've been through more than I will ever experience in a lifetime, but I promise that it's going to be OK."

McDonald shared that her family was reunited in a 2:50 p.m. Facebook post and that both boys were out of surgery.

"Now it's time to step forward into the new chapter of our life," she wrote. "I'm ready to fight and I know you are too. Thank you, Dr Goodrich, Dr Tepper, Kamilah, Martine, Dr Kahana, Dr Mann and everyone else at Montefiore. Your hands performed a miracle today. We love you."

The family set up a GoFundMe page to help with medical expenses. It has raised over $194,000, surpassing its $100,000 goal.