Star Wars: 10 Things You Didn't Know About R2-D2
2. R2-D2 Was Anakin's Wedding Gift
Padme and Anakin had a unique relationship right from their very first meeting on Tatooine, and their droids were a big part of this. R2 was accompanying Padme when she arrived at Mos Espa, while Anakin excitedly showed her C-3PO, the protocol droid he was building.
Years later, Anakin and Padme would reunite when she arrived on Coruscant as Senator for Naboo, and Anakin was assigned as her bodyguard following attempts on her life. R2-D2 and C-3PO would reunite too, when Anakin travelled back to Tatooine with Padme to try and save his mother.
Spending so much time in each other's company, the romance between the young Jedi and politician grew, and the pair married in secret. As marriage was forbidden by the Jedi Order, they couldn't have any obvious signs of their love, so they chose a more subtle symbol, exchanging their droids.
It made a lot of sense, too. As a Jedi Knight, Anakin would have a central role in The Clone Wars and needed an astromech to help out in battle, while as a senator, a protocol droid would be much more useful to Padme in her political life. It also meant that the two droids were also the only witnesses to their secret wedding.