The first ever official "TLC" match took place at SummerSlam 2000 between The Hardy Boyz, The Dudley Boyz and Edge and Christian. (Watch it here). The match served as an undercard bout for the WWE Tag-Team Championships, which were held at the time by Edge and Christian. This match was the direct result of a series of ladder matches involving some (or all three) of the aforementioned tag-teams.
At the WWE No Mercy pay-per-view in 1999, the managerial services of Terri Runnels was on the line in a tag-team ladder match between The Hardy Boyz and Edge and Christian. (Watch it here.) The match ended up being one of the craziest, action-packed, exciting and dramatic contests wrestling fans in the WWE had ever seen. They took the ladder match that was popularized by Shawn Michaels and Razor Ramon at WrestleMania X to the next level, and really cemented their status in the company in that one match. Both teams not only received standing ovations from the fans at the conclusion of their match at No Mercy, but again the following night on RAW when they simply came to the ring. WWE realized that the two teams had revolutionized the ladder match concept and decided to run with it.
In the months that followed, Edge and Christian would square off against The Dudley Boyz in a series of tables matches. The reason for the table match was due to The Dudley Boyz having a popular spot in matches where Bubba Ray Dudley would shove D-Von Dudley, and yell out "D-Von...get the tables!" The two would then put their opponents through the table to win their match.
As that feud was going on, WWE ran with the idea that The Hardy Boyz were the king of the ladder matches, having the two compete in additional matches using the ladder, including some singles matches where one-half of the team would challenge main event opponents, such as The Undertaker. (Watch it here).
At the same time, Edge and Christian popularized a spot in their matches called the "Con-Chair-To." This was a spot where each guy would blast their opponent in the side of the head, simultaneously, on opposite sides, with chairs.
That was how it all came together. The Dudley Boyz were known for tables. The Hardy Boyz were known for ladders. Edge and Christian were known for chairs. It only seemed logical at that point to have all three teams compete against each other in a three-way tag-team match called "Tables, Ladders and Chairs."
Flash-forward back to SummerSlam 2000, where the first official "TLC" match took place. Edge and Christian ended up winning the match that night to retain their WWE Tag-Team Championships. The match was again so critically acclaimed that they ended up doing a "TLC" rematch on the grandest stage of them all -- WrestleMania.
The event was WrestleMania X-Seven, which is considered by many to be among the best WrestleMania events from top-to-bottom in WWE history. One of the reasons it was considered one of the best is because of the TLC match between The Hardyz, The Dudleyz and Edge and Christian (Watch it here). All three teams stepped it up a notch in this match, where a number of highlight spots took place. Everyone remembers Jeff Hardy's insane "Swanton Bomb" off the giant 16-foot ladder. (Watch it here). Everyone remembers Edge leaping off the giant ladder to spear Jeff Hardy, who was dangling from the loop that holds the belts above the ring. (Watch it here). Edge himself calls that the single greatest snapshot of his entire career.
A total of eight TLC matches would take place before WWE decided to create an entire pay-per-view around the match concept in 2009. WWE Tables, Ladders and Chairs 2009 would feature main events where there would be a ladder match, a tables match, a match where steel chairs were legal as weapons and the final bout of the evening would be an actual TLC match. The TLC pay-per-view replaced what was the original WWE pay-per-view show in December, "Armageddon."