The first documents that evidence Cotopaxi's eruptions are of 1534. In these eruptions the city of Latacunga was three times destroyed till 1877. Its last eruption was in 1942. This is an active volcano. http://www.hotelfinlandia.com.ec/quito_cotopaxivolcano.html

Several times. Just since 1738, it has erupted 50 times.

There have been more than 50 eruptions of Cotopaxi since 1738. http://en.wikipedia.org/wiki/Cotopaxi

Wikipedia says of Cotopaxi: There have been more than 50 eruptions of Cotopaxi since 1738. Numerous valleys formed by powerful lahars (mudflows) surround the volcano. This poses a high risk to the local population, their settlements and fields. During a war between the Incas and the Spaniards in 1534, the volcano erupted and put an end to the fighting as both fled from the battlefield.[citation needed] Cotopaxi's most violent eruptions in historical times occurred in the years 1744, 1768, and 1877. In the 1877 eruption pyroclastic flows descended all sides of the mountain, with lahars traveling more than 100 km into the Pacific Ocean and western Amazon basin draining the valley.[5] There was a major eruption in 1903 through 1904, and some minor activity in 1942 as well as 1975 but it did not produce any major events. In the most recent case, fumarolic activities and sulfuric emissions increased and ice around the inside and on the southeastern side of the cone started to melt. The main danger of a huge eruption of Cotopaxi would be the flow of ice from its glacier. If there were to be a very large explosion, it would destroy most of the settlements within the valley in the suburban area of Quito (pop. more than 1,000,000).[citation needed] Another city which would be in great danger is Latacunga which is located in the south valley. In 1744 and 1768 an eruption destroyed the colonial town of Latacunga. Experts believe another eruption may come soon.