mairriage seat la18- 
mariage seat la17-e18 n 
A chair bearing the initials and usually the date of marriage of a couple. 

And Chris held on to Ewan's hand and bent her head and listened to him, the minister; and he asked God to bless their union, to give them courage and strength for their difficulties that the years might bring them, to make fruitful their marriage
Lewis Grassic Gibbon 1932 'Sunset Song'