Original: The chain's first store opened in 1964 in Hamilton, Ontario under the name "Tim Horton Donuts" (the name later being abbreviated to "Tim Horton's", and later still changed to "Tim Hortons" without the possessive apostrophe).
Simplified: The companies first store opened in 1964 in Hamilton, Ontario under the name "Tim Horton Donuts" (the word donut would later be dropped and the company name ended up as just "Tim Hortons", and later was changed to "Tim Hortons" without the apostrophe).