Last Updated Jan 18, 2016 2:00 AM EST
LANDSHTUL, Germany -- President Obama said this weekend's prisoner swap with Iran was a victory for American diplomacy.
Americans freed from Iran were arriving in Germany to be reunited with their families. A fifth American, a student, was released separately on Saturday.
Matthew Trevithick, Boston University graduate who'd been studying the Farsi language in Tehran, arrived back in Boston Sunday evening, The Boston Globe reports.
Following the exchange, the United States and five other world powers lifted economic sanctions on Iran, and freed billions in frozen assets implementing the landmark Nuclear Deal reached last July.
Arriving in Geneva on a Swiss Air Force plane late on Sunday, the three Americans were safe at last on European soil. A fourth American was freed as part of the exchange, but was not on the same plane as the others.
One of those American's was Jason Rezaian, the Tehran reporter for the Washington Post. In Germany, he shook hands with the State Department's Brett McGurk who led negotiations for the prisoners' release.
Rezaian was jailed a year and a half ago. He was charged with spying.
Pastor Saeed Abedini, was arrested in 2012, alleged to have organized underground Christian churches in Iran.
And Amir Hekmati, a former U.S. Marine, was picked up in 2011 while visiting his grandmother -- and charged with espionage.
CBS News' Adriana Diaz caught up with Hekmati's sister Sarah just as she boarded a plane to be reunited with her brother.
"I'm in a fog, this is like surreal. I'm still in disbelief and honestly everything just happened so quickly that I don't think it'll hit me until I'm hugging him," she said.
All three Americans were released from Tehran's infamous Evin Prison after 14 months of top-secret diplomatic bargaining that started on the sidelines of the nuclear talks.
President Obama waited until they were out of Iranian airspace before saluting them.
"Today, we're united in welcoming home sons and husbands and brothers who, in lonely prison cells, have endured an absolute nightmare," Mr. Obama said.
Bahram Mecanic and Khosrow Afghahi were also freed. They are two of the seven prisoners the U.S. released from its jails as part of the swap. All were accused of selling technology to Iran in violation of American sanctions.
And finally -- there's a mystery man, the fourth American prisoner who was released along with the others, but apparently stayed behind in Iran. All we know is his name: Nosratollah Khosravi Roosari.
The three other Americans will spend their first night of freedom at the Landstuhl Military Hospital in Germany -- which has long offered a warm welcome and medical care to U.S. hostages and prisoners on their way home.