Solkar of Vulcan was the father of Skon, forefather of Sarek and second forefather of Spock. (Star Trek III: The Search for Spock)
He was the first Vulcan ambassador to Earth.
As such, he was the answer to a downloadable crossword puzzle an ensign was trying to figure out while forced to live in the catwalk for several days. She didn't know the answer, but Captain Archer helped her out. (ENT: "The Catwalk")
Apocrypha
According to the Enterprise novel Last Full Measure, Solkar, along with T'Pau and Soval, were the three Vulcans that signed the Federation Charter on August 12, 2161.
According to the Star Trek Customizable Card Game, Solkar was the Vulcan captain of the T'Plana-Hath who greeted Zefram Cochrane in Star Trek: First Contact.
In an unpublished interview with Larry Nemecek, "The Catwalk" writer Mike Sussman believes this as well, citing the wording in Archer's dialog in "Horizon" in which he refers to Cochrane's first contact and says, loosely, "I don't remember anyone going after the Vulcan ambassador with pitchforks and torches when they first landed."