Here is an interesting story I found in the Japan Times about a 600 year old apology.
Apology for slight 600 years ago
To offer apologies for an unkindly act committed by their ancestors 600 years ago, the people of Ayukawa, a village in Wakayama Prefecture, will offer mochi (dumplings of glutinous rice) to the Kamakuragu Shrine in Kamakura, Kanagawa Prefecture, dedicated to the memory of Prince Morinaga on Aug. 19, when the 600th anniversary of the prince's death will be celebrated.
Defeated in his battle against rebels, Prince Morinaga with a few retainers was obliged to hide, and on Oct. 15, 1331, he passed through the village of Ayukawa. The prince and his party were fatigued and hungry, having eaten nothing the whole day. At the houses of the villagers they asked for some food, but they were refused because of the disturbed state of affairs at that time.
Soon after that, the villagers learned that the person to whom they refused to give mochi was Prince Morinaga. Such a discourteous act toward an Imperial Prince was something that the villagers could not think of. So to atone for their wrong, they resolved not to make and eat mochi forever. Thus for more than 600 years the village people never made mochi even on New Year's Day.
This year the villagers have finally decided to make mochi on the occasion of the 600th anniversary of the prince's death — and to offer them in his memory at the Kamakuraga Shrine.