P. Remus Snow is the firstSnow Family member we can go back to. He was the one who brought Panem together under a new central government and created the Districts.
The one who started it all. Remus Snow worked his entire adult life to unite the Former United States, which had been disbanded centuries ago, under a single government again and ensure that the country's natural resources were distributed evenly to all people. (Unified Distribution System or UDS) He drew the lines for the Districts and assigned them a niche according to what resources were abundant in their area. The mountain-set city were he had been born and grew up would be the new Capitol. At age 34 he was declared President and ruler of the new nation of Panem. He made yearly visits to each District to ensure that his systems were being enforced and all citizens were being well cared for.
His idea was to regulate and equalize trade and commerce in the nation, and he did it well. Under his plan the "Unified Distribution System" all citizens in the Districts and the Capitol were supplied with what they needed. Of course the Capitol and Districts closer to it had more luxuries, but no one under Panem's rule went to bed hungry.
Remus went into a state of deep mourning and isolation for about five years after Glencora's death, and his Cabinet of old friends ran the country. While they stuck by his policies, some of them felt that he was no longer fit to rule even in name. The current patriarch of the Stone family was even set on claiming the Presidency for himself. He ordered the assassination of Remus and his young son Coremus, but one of his supposed co-conspirators was a spy. Said spy went to Remus immediately and warned him of the plot, snapping the President out of his melancholy state and into protective dad mode.
All those involved in the plot were executed privately except for Stone, who was beheaded publicly as a show of Remus's power and unwillingness to let harm come to his family. After making an example of them the people in the Capitol that tried to take his place, Remus Snow made it official in writing and in public announcement that the Presidency of Panem would be a hereditary office, passing to the eldest child of the current leader.
He outlived his dear Glencora by 29 years total, but he never recovered from her death and never sought to marry again. He died at the very old age of 93, and he requested to have a mausoleum built to house the bodies of Glencora and himself. This mausoleum would become the burial place for all the immediate members of the Snow family.
His reign was looked back on by both Capitol and District as a Golden Age of the nation.