Clockwork Dynasty by Daniel H. Wilson

Begin at the court of Peter the Great where a talented clockmaker has created an array of avomat, automated humans and animals, for the pleasure of the Czar. Peter and Elena, his little sister, are cherished and taught everything of court life and the world around them. Being machines, they outlive everyone at court and over the centuries have learned to hide among humans careful never to reveal their secret identities to them. Fast forward to recent times where a young anthropologist named June has discovered a strange relic in her grandfather's things. This relic belongs to an avomat and soon June is immersed in a world that has always been around her but hidden. As June vows to help Peter she will soon fall into a dangerous world of the avomat and the dark forces that threaten humanity unless they can stop them. A delicious mix of steampunk robotic love and historical fantasy that I did not want to end.