The Shifchah of Rabah bar Zutra fled. He despaired from her. He went and asked R. Chaninah and R. Yehoshua ben Levi. They said, he cannot force her to serve him.

He asked if he must write a Get Shichrur for her. They said, if you wrote, you did properly.

(R. Chaninah citing R. Yishmael bei Rebbi Yosah): If a slave married a Bas Chorin in front of his master, he goes free.

(R. Yochanan): Last night, I sat and learned 'if one wrote a Kidushin document for his slave (the slave is Mekadesh a Bas Chorin) or a Nisu'in document to his Shifchah (her master is Mekadesh her), Rebbi says, [the slave] acquired [freedom]. Chachamim say, [the slave] did not acquire;

The first Tana (R. Yishmael bei Rebbi Yosi) holds like Rebbi, that he acquired.