Professor Langford was the archaeologist who discovered the stargate in 1928 in Giza, Egypt. He was introduced in the movie.
It wasn't until 1945 when President Roosevelt gave funding for Professor Langford to study the stargate. The President thought that the device might be a weapon. Although Langford's daughter, Catherine, was very intelligent, there was no place for a twenty-one-year-old woman in scientific government research in the 1940s.
Professor Langford had a team of archaeologists and linguists translate the coverstone. They used Budge as a reference and translated the name of the device as "Doorway to Heaven". Based on this name, Langford believed that it meant death. Even though he dismissed Professor Ernest Littlefield's suggestion that the symbols of the stargate translated into destinations, he still gave Ernest permission to walk through the wormhole they were able to establish by accident. After Ernest was cut off from the group when the wormhole disengaged, Langford told Catherine, who was engaged to be married to Ernest, that Ernest had died in an explosion in the lab. Catherine never married.
It wasn't until 1997 when Daniel Jackson was reviewing the research film from Professor Langford's 1945 project that Ernest's fate had been discovered. Catherine figured that her father had lied to her to spare her from the truth that Ernest had chosen his research over her. Catherine was reunited with Ernest through the help of SG-1 and they decided to live the rest of their lives together.
No mention is made of when Professor Langford died.
--DeeKayP 18:49, 8 Jan 2005 (PST)