It's the 21st CENTURY.
The Big Bang Theory Season 5, Episode 17
Thailand has had the fork
since the latter half of the 19th CENTURY.
The Big Bang Theory Season 1, Episode 2
...was a third CENTURY Roman priest
who was stoned and beheaded...
The Big Bang Theory Season 3, Episode 15
Pizza dates back to the 16th CENTURY...
The Big Bang Theory Season 4, Episode 9
Corn dogs didn't come into existence
till the first half of the 20th CENTURY.
The Big Bang Theory Season 2, Episode 2