Linnet by Sally Watson
Linnet, a too-trusting upper-class young lady of fourteen, ran away to seek adventure in the heart of sixteenth-century London. Along the way she met Sir Colin Collyngewood, a gentleman, and accepted the ride he so kindly offered her. That was her first mistake. Her second was in accepting his hospitality, although by that time, she had little choice. A fascinating and intriguing book based on an actual historical plot.