All the way back in the 17th century, two separate astronomers 'discovered' the object pictured above—a supernova called CK Vulpeculae (otherwise known as Nova Vulpeculae 1670, or Nova Vul 1670). The first time, in mid 1670, Pere Dom Voiture Anthelme made note of it. Just two years later, it was independently confirmed by Polish astronomer Johannes Hevelius.
Nearly 350 years later, Nova Vul still shines, which demonstrates that the universe works on a different timetable than that of Earth. Its rich history includes a series of eruptions that were so bright, they could even be seen with the remedial technology of the times. The most powerful of which lasted well over two years throughout 1670 and 1672.
At its peak, it was a 3rd magnitude object, but it quickly faded back into obscurity over 100 days. Naturally, the story doesn't end there; in the subsequent year, when the object was rediscovered by Hevelius, it remanifested in a big way—reaching a visual magnitude of 2.6. Just to disappear as quickly as last time.
Of course, just because astronomers could see and document the increases in luminosity, it doesn't automatically mean the mechanism causing the outburst was determinable; that didn't become possible until the 20th century. The European Southern Observatory (ESO) explains further:
This specific object (or should I say 'objects,' plural) can be found within the confines of the obscure constellation of Vulpecula, near the border of the Cygnus constellation.