The Sororium Tigillum, which translates as the "sister's beam", was a wooden beam said to have been erected on the slope of the Oppian Hill in Ancient Rome by the father of Publius Horatius, one of the three triplets Horatii. Publius Horatius was required to pass under the beam, as if under a yoke, following the decision of the people's assembly not to punish him for the murder of his sister.
- Livy, Ab urbe condita, 1:26
- CIL vi. 32482
- Platner, S. B, and T. Ashby. 1929. "Tigillum Sororium." In A Topographical Dictionary of Ancient Rome. Oxford: Clarendon Press.