Indirect speech, also known as reported speech, reports people's words and thoughts by giving our own version of a person's exact words, as in He asked me what time it was.
While it is often said that both the verb used to report what was said (the reporting verb) and the verb reported (the reported verb) go one tense back this is, in fact, quite an oversimplification. It will depend on such things as when the report is being made, whether the thing reported is still considered to be true and if the speaker is still alive.
Let us take as an example the statement, "I love you" and consider how it might be reported.
Both verbs in present
A young person on the phone speaking to their significant other. The young lady says "I love you." Her partner shouts to anybody who might be interested "She says she loves me!"
Same situation but the lady tells our poor listener that she loved him in the past. He might report "She says she loved me."
Next, let's imagine our jilted lover in the pub, now aware that the young lady's affections are directed elsewhere. We might hear "She said she loved me."
Reporting the dead
Even if the thing reported is still believed to be true we will probably put the reported verb in the past if the person being reported is no longer with us: "Galileo maintained that the earth moved."