|“||But I'm not going to take the chance and let them starve, because of some ridiculous rule that your ancestors invented.||”|
–Feyre's response to the Tithe, A Court of Mist and Fury
The Tithe is a biannual event occurring in the Spring Court. During the event, every faerie in the Spring Court is expected to give its High Lord a gift. The gift they give is dependent on their income and status. In exchange, the High Lord promises to protect them and help them when he can.
The gifts that the Spring Court receive are used to keep the High Lord's estate functioning. It is used to pay for sentries, food and servants.
If a faerie is unable to pay the Tithe, then they will get three extra days. After then, if the faerie is still unable to pay, then the High Lord of the Spring Court is expected to hunt them down and impose judgement.
The Tithe is an ancient event that occurs within the Spring Court twice a year. Tamlin's father and grandfather both enacted the Tithe on the citizens in the Court, during their respective time in power. However, during Amarantha's control over Prythian, Tamlin refused to hold the Tithe, and thus the citizens of the Spring Court did not pay their taxes.
Several months after the events in Under the Mountain, Tamlin announced the that the Tithe will be occurring. Tamlin, however, decides to grant the court an extra month to celebrate Amarantha's defeat and to gather funds for the upcoming Tithe.
The Tithe finally occurs a week after Feyre returns from her first week at the Night Court. Due to Feyre's relationship with Tamlin, she is expected to sit beside Tamlin and observe. Lucien's role is to keep track of who pays their Tithe and who doesn't. Tamlin is the High Lord, and thus expected to hunt down any faerie who doesn't pay the Tithe. The event occurs within the receiving room, a large room that appears identical to a throne room.
During the Tithe, both Lesser Faeries and High Fae visit the receiving room to give payment. Tamlin receives multiple gifts including gold, jewels, chickens, crops, mushrooms, a golden fleece and a jar of jam. A water-wraith enters the room and explains to Tamlin that she is unable to pay her Tithe, as there are no fish within the lake. She pleads with him to make an exception, but Tamlin refuses. He angrily tells her that she must pay, otherwise she will have to pay the consequence.
Feyre watches the proceedings and is deeply offended by Tamlin's actions. Unlike the High Lord, she is sympathetic towards the water-wraith. Feyre has suffered from poverty herself and understands what it is like to go without food. Thus, she urges for Tamlin to make an exception. She explains that the gifts they received are unnecessary, but Tamlin refuses.
Angrily, Feyre storms away and meets with the water-wraith. She gives her all the jewellery she has on her possession, allowing the water-wraith to pay her Tithe. The water-wraith asks what she wants in return, but Feyre clarifies that she wants nothing. In spite of this, the water-wraith tells her that she will never forget the kindness.
Once he finds out about her interaction with the water-wraith, Tamlin is outraged as he believes that she undermining the rules of the court. Feyre tells Tamlin how it felt when she suffered from poverty, and why she gave the jewellery to the water-wraith. Tamlin ignores her reasons and is still deeply outraged at her actions.
- The High Priestesses grant sacred hunting rights for the Tithe. Ianthe is one of the priestesses who is able to do this. 
- Though some citizens in the Night Court have to pay taxes, there is no equivalent of the Tithe in the court. 
- In the real world, a tithe is a one-tenth part of something, paid as a contribution to a religious organization or compulsory tax to government. Traditional Jewish law and practice has included various forms of tithing since ancient times.