A bronze sword more than 3,000 years old, which is so well-preserved that it “almost still shines”, has been unearthed in southern Germany, officials say.

The Bavarian state office for the preservation of historical monuments (BLfD) said the sword, which is believed to date back to the end of the 14th century BC — the middle of the bronze age — was found during excavations last week in Nördlingen, between Nuremberg and Stuttgart.

The sword has an octagonal hilt and comes from a grave in which three people – a man, a woman and a boy – were buried in quick succession with bronze objects, the BLfD said this week. It was not yet clear whether the three were related to each other and, if so, how.

Mathias Pfeil, the head of the BLfD, said: “The sword and the burial still need to be examined so that our archeologists can categorise this find more precisely. But we can already say that the state of preservation is extraordinary. A find like this is very rare.”

It is unusual to find swords from the period, but they have emerged from burial mounds that were opened in the 19th century or as individual finds, the BLfD said.