Transcendentalism and Romanticism had a lot of similarities.
Both movements were born as reactions to strict traditions, laws and religious
rules of the time. Both also opposed Calvinism, a religious teaching that
implies that the future of humans is predetermined. These two philosophies
emphasized individualism and inspiration from nature. Romanticism was a
reaction against realism and objective reasoning and transcendentalism was a
protest against that Unitarian church which was the religious tradition and
dogma at that time.
I hope this helps.