Per her wikipedia page, the Princesse de Lamballe was married by proxy at age 17 to a great grandson of the sun king. The wedding was followed by a bedding ceremony, but Wikipedia doesn't say how that worked with the bride and groom in different places.
What would that ceremony have looked like? Did someone stand in for the groom?
Wikipedia source: https://en.m.wikipedia.org/wiki/Marie_Th%C3%A9r%C3%A8se_Louise_of_Savoy,_Princesse_de_Lamballe
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Marriage by proxy used to be allowed in Roman Law (only for men: a woman could only be married once she was led to her husband's house) but it fell out of favour for a few centuries until it reappeared in the 1200s. One of the earliest instance was the marriage of Frederick II, Holy Roman Emperor and Isabella of England in 1235, which took place in the Palace of Westminster where the Emperor was represented by his chancellor Pietro della Vigna and the Duke of Brabant (Blum, 1917).
The legality of marriages per procuram was confirmed by a decretal of Pope Boniface VIII, and later reconfirmed by the Council of Trent in 1563, which required that matrimonial consents must be exchanged before a priest and two witnesses. There was some debate between canonists, but it was eventually agreed that marriage by proxy was acceptable provided that some requirements were fulfilled (Blum, 1917). In any case it was practiced regularly by European monarchs from the 13th century to the early 19th century (Napoleon I married his second wife by proxy in 1810).
One dynasty that practiced regularly marriage by proxy was the House of Habsburg, and they added a special twist: a simulacrum of marriage consummation which consisted in having the proxy groom, usually a family member, an ambassador or a special envoy, share the bed of the bride. This was not just to satisfy canonists attached to copula carnalis, but to add a layer a protection: even more than marriages in persona, marriages per procuram could be threatened by a variety of issues, legal and otherwise, that could lead to their cancellation. This symbolic consummation was derived from the germanic tradition of the Beilager nuptial ritual, which included a public dimension (Debris, 2005).
The 18-year-old Duke Maximilian (future Maximilian I, Holy Roman Emperor) was married by proxy to Mary, Duchess of Burgundy in 1477. He was represented by the Duke of Bavaria and French chronicler Delepierre tells how it went:
Mary of Burgundy was led to her apartment by torchlight, together with the Duke of Bavaria who accompanied her. He was covered on one side by silver armour, and had a naked sword in his hand, which he held between him and the princess as a sign that the Duke Maximilian would defend it with his sword. During the night, four archers kept watch, according to the custom of these kinds of princely marriages, next to the bed on which they were both lying.
Generally, the symbolic consummation did not last the whole night, but only a few minutes in public. Typically, the proxy groom lay on the bed beside the princess. One of his legs was undressed, while the other touched the ground, and the rest of his body was armed. A naked sword was put between the groom and his bride, which symbolised the protection offered by the husband to his wife, or a mark of chastity, like Tristan lying platonically beside Yseult (Debris, 2005).
Another example of this custom is the next marriage of Maximilian, now 31, to 13-year old Anne of Britanny in 1490. Maximilian's envoy Wolfgang de Polheim climbed into Anne's bed with his right arm and leg undressed, and a naked sword between him and the bride. Chronicler Jacques Unrest wrote that this ritual was a tradition for Austrian princes (Debris, 2005). This practice seems to have been found bizarre outside Austria, and Maximilian was mocked for it (Blum, 1917). In 1501, Philibert II, Duke of Savoy, married by proxy Margaret of Austria (daughter of Maximilian I): he sent his brother René, the "Bastard of Savoy" and many jewels. After the dinner and a dance, the bride went to her bed and the Bastard climbed next to her with one naked leg, in front of all the guests. They exchanged nice words, he asked for (and received) a kiss, she gave him a diamond ring, and then they got up and left (Debris, 2005).
Other houses seem to have had similar practices: in 1626, after the church wedding, Catherine of Brandenburg (Hohenzollern-Prussia) and Prince Georg Rákóczi (proxy of Prince of Transylvania Gabriel Bethlen) sat on a bed together for a while in public as a symbol of the consummation of the marriage (Deák, 2012).
Now what about the Princess of Lamballe?
Marie Thérèse Louise of Savoy, future Princesse de Lamballe, was a descendant of Charles III (Philibert II's half brother). Her marriage to the French prince of Lamballe took place in Turin, with her own brother, 24-year-old Victor-Amedée acting as the groom by proxy. Papers were signed, and the marriage was blessed by cardinal della Lanze. According to 19th century historian Adolphe de Lescure, an apologist for the princess (Lescure, 1864):
On leaving the chapel, the King gave the princess his hand with joyful and paternal gallantry and led her into the parade hall, where, as was customary, the new Madame de Lamballe lay all dressed up, in the presence of the whole court, with the prince her brother, who only took off his shoe on one leg, while on the other he had a boot and a spur. A bizarre and thoughtful ceremony, whose aim seems to have been to represent the consummation of the marriage and to assure the bride of her dower, even if the bridegroom died before her arrival.
Later historian Raoul Arnaud used as primary sources several accounts of the ceremony written by Italian officials and provides in his biography of the princess an extremely detailed description of the marriage (and notably of the paperwork involved). He confirms that the prince Victor did act as a proxy, and Italian sources noted that the princess was amused by the way her brother "played husband with her". However, Arnaud says that story of the "symbolic consummation of the marriage in front of the whole court" is just a "pleasant tale" and that the bride left immediately for France (Arnaud, 1911). This seems indeed more plausible, particularly if Arnaud could access Italian archives. Lescure did too, but he seems to have relied on the testimonies of members of the House of Savoy, and this may have been a tale passed through generations since Philibert II. According to Debris (2005), the Habsburgs used the "fake consummation ritual" from the last quarter of the 15th century to the early 16th and it seems odd that a germanic mediaeval/renaissance practice, already considered in its time as odd outside germanic territories, could survive in Italy for another two centuries.
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