The palace on Saturday said that both Duchess Meghan and Prince Harry gave speeches at the reception, as did Prince Charles. Prince William introduced them.
Sir Elton John performed, the palace announced, "in recognition of the close connection he has with Prince Harry and his family."
The lunchtime reception will be followed later in the day by a smaller reception with 200 VIP guests.
Here's what we know about the first reception's menu:
THE CAKE
Here's how the palace describes the cake:
"Designed by Claire Ptak, the wedding cake features elderflower syrup made at The Queen's residence in Sandringham from the estate's own elderflower trees, as well as a light sponge cake uniquely formulated for the couple. A filling made from Amalfi lemon curd and elderflower buttercream ties all the elements together. The cake is decorated with Swiss meringue buttercream and 150 fresh flowers, mainly British and in season, including peonies and roses."
OTHER SWEETS
In addition to the cake, guests will be served sweet canapes:
Champagne and pistachio macaroons
Orange creme brulee tartlets
Miniature rhubarb crumble tartlets
SAVORY
The savory food included both canapes and food bowls, according to the palace.
Canapes:
Scottish langoustines wrapped in smoked salmon with citrus creme fraiche
Grilled English asparagus wrapped in Cumbrian ham
Garden pea panna cotta with quail eggs and lemon verbena
Heritage tomato and basil tartare with balsamic pearls
Poached free-range chicken bound in a lightly spiced yogurt with roasted apricot
Croquette of confit Windsor lamb, roasted vegetables and shallot jam
Warm asparagus spears with mozzarella and sun-blush tomatoes
Food bowls:
Fricassee of free-range chicken with morel mushrooms and young leeks
Pea and mint risotto with pea shoots, truffle oil and parmesan crisps
Ten-hour slow-roasted Windsor pork belly with apple compote and crackling
DRINKS
Pol Roger Brut reserve non vintage champagne
A selection of wines
An apple and elderflower mocktail, made with the same elderflower syrup used in the wedding cake
Sandringham Cox's apple juice