You could use this phrase as a way of saying “I’m sorry”, or “my bad”. If you forgot to pick something up for a friend or upset someone unintentionally this is a way of saying that you recognise your mistake, and are sorry for it.
The origin of Asche auf mein Haupt can be traced all the way back to Biblical times. Ash Wednesday, a Christian Holy Day, marks the start of the Lent period leading up to Easter, the day on which Christians believe Jesus was resurrected.
The ashes symbolize both death and repentance. During this period, Christians show contrition and mourning for their sins, because they believe Christ died for them.
In these times, there was also a tradition of throwing ashes on people’s heads and clothes on sad occasions. This was considered to be an expression of one’s own grief.
The Latin phrase Mea Culpa, which means “through my fault” and comes from a prayer of confession in the Catholic Church, is also understood to be an accurate translation for Asche auf mein Haupt.
If you choose to use this phrase in place of “Entschuldigung” or “Tut mir leid”, which are common ways to say sorry, be careful of your tone because Asche auf mein Haupt is sometimes also used ironically!
The phrase is most commonly used in southern Germany, due to its Catholic roots and traditions.
Ich habe vergessen, dir deinen Buch mitzubringen. Asche auf mein Haupt.
I forgot to bring your book. I'm sorry.
Ich habe einen Fehler gemacht. Asche auf mein Haupt!
I made a mistake. My bad!