1593 - A Spanish man, in his will, bequeaths his telescope to his widow. Don Pedro de Carolona in Barcelona Spain. This isn't telling us that he invented the telescope, just that he had one before the traditionally accepted 1608 date of its invention. (more info here)
1608 - Hans Lippershey applies for a patent for a refractor telescope
1609 - Galileo Galilei makes a refractor telescope and turns it to the skies
1616 - Niccolo Zucchi constructs the first reflecting telescope
1630 - Christoph Scheiner constructs a keplerian telescope based on Keplers design
1650's - Christiaan Huygens improves on the design of the refractor telescope and build some large scopes
1663 - James Gregory designs the first reflector telescope but does not build one for several years because of difficulties in construction technique. This style of telescope is called "The Gregorian Reflector".
1668 - Sir Isaac Newton builds the first workable reflector telescope
1672 - Laurent Cassegrain improves on the Gregorian design by creating the Cassegrain telescope
1721 - John Hadley produces the first workable Gregorian telescope
1733 - Chester Hall designs and builds the first achromatic lenses which dramatically improved the performance of refractor telescopes
1789 - William Herschel builds the largest telescope of the 18th Century. It was a giant reflector with a mirror that was 49 inches wide.
1895 - The largest refractor in history is completed at the Yerkes Observatory at the University of Chicago in Williams Bay, Wisconsin. The 40 inch lens was built by Alvan Clark.
1908 - The 60 Inch Mount Wilson reflector is completed
1910's - George Willis Ritchey and Henri Chretien co-invent the Ritchey-Chretien telescope which is a design used in many modern observatory telescopes.
1917 - The 100 inch Hooker telescope is completed
1944 -Dmitri Dmitrievich Maksutov invents the Maksutov telescope
1948 - The 200 Inch Hale reflector at Mount Palomar observatory is completed
1965 - the 238 Inch Large Alatazimuth Telescope in Russia is completed
1990 - The Hubble Telescope was launched into space. This telescope has brought us images and information that is unprecedented. It is a Ritchey Chretien design and has a primary mirror that is 2.4 meters wide (94.5 inches)
2005 - The Large Binocular Telescope (LBT) achieves first light. This telescope has the largest single piece of glass mirrors. Each mirror is 8.4 meters (330 inches) in width and when used together they create the equivalent of a mirror that is 11.8 meters (464 inches) across which is currently the largest light collecting size on Earth. It is located in Mount Graham International Observatory in Arizona
2005 - The South African Large Telescope (SALT) achieves first light. It has a segmented primary mirror that is 10.4 meters in diameter (409 inches)
2013 - The James Webb Space Telescope is scheduled for launch. It will have a 6.5 meter diameter mirror.
2017 - The Giant Magellan Telescope (GMT) is scheduled to achieve first light. It will have an array of seven solid glass mirrors that will combine to be the equivalent of a 24.5 meter (80 foot) telescope. Which will make it much larger than anything yet built. (Appproximately 960 inches!)
The Telescope Nerd 
