The Bute Mazer, also known as the Bannatyne Mazer is a medieval communal feasting cup of a type known as a mazer. Dating to around 1320, it is the oldest Scottish mazer still surviving. The cup has long been associated with the Isle of Bute, on the west coast of Scotland. Its alternative name derives from Ninian Bannatyne, Laird of Kames, who owned the cup in the 16th century and had his name engraved on the rim. The mazer is now in the collection of the National Museum of Scotland in Edinburgh.
The Bute Mazer may have been used by King Robert the Bruce (reigned 1306–1329) at Rothesay Castle on Bute. Rothesay at this time was the seat of Walter Stewart, 6th High Steward of Scotland (1293–1326). The six coats of arms on the mazer represent six leading Scottish noble families, including that of Walter Stewart, and the cup could have been a gift to the king from any of them. Three of the coats of arms on the cup represent signatories of the Declaration of Arbroath, a statement of Scottish independence written in 1320.
The bowl of the cup is made of maplewood, while the foot is silver. Silver and silver-gilt hinged straps and a rim were added in the 16th century, when the cup was owned by the Bannatynes. This work may have been carried out by Peter Lymeburner, a goldsmith in Glasgow. In the bottom of the bowl is a metal boss, decorated with a recumbent and grinning lion in high relief, who looks up at the viewer, and is surrounded by six coats of arms. The lion is thought by some to represent Robert the Bruce, while the six shields represent six of his supporters (in clockwise order starting at 6 o'clock):
- House of Stewart, as represented by Walter, the High Steward
- Douglas, as represented by Bruce's companion, Sir James Douglas (1286–1330)
- Walter FitzGilbert (died c.1346), ancestor of the Dukes of Hamilton
- John FitzGilbert, Baillie of Bute and possibly brother of Walter
- Crawford of Loudoun
- Menteith, a branch of the Stewart family
It has been observed that Douglas is at the lion's right hand, to represent Sir James Douglas' position as Bruce's principal commander, while Stewart is between the lion's paws, since Walter Stewart was married to the King's daughter Marjorie. Their son inherited the throne as King Robert II in 1371, the first monarch of the House of Stewart.