did they participate in any wars?
Yes, the "First Battle of Beleriand".
Elf (Middle-earth)
After the First Battle of Beleriand, during the first rising of the Moon, the Noldor arrived in Beleriand. They laid a siege around Morgoth's fortress of Angband, but were eventually defeated. The Elves never regained the upper hand, finally losing the hidden kingdoms Nargothrond, Doriath, and Gondolin near the culmination of the war. 
where did the elves come from in lord of the rings Middle-earth what are these creatures? They are a fictional race inhabiting Middle-earth in the remote past. They are immortal. have they been depicted in any book? Yes, in "The Hobbit", "The Lord of the Rings” and "The Silmarillion". what dialects do they speak? Quenya
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Elf (Middle-earth) [SEP] Wars of Beleriand
In Beleriand, Elwë was eventually found, and married Melian the Maia. He became the overlord of Beleriand, naming himself Thingol (Sindarin: "Grey-cloak"). After the First Battle of Beleriand, during the first rising of the Moon, the Noldor arrived in Beleriand. They laid a siege around Morgoth's fortress of Angband, but were eventually defeated. The Elves never regained the upper hand, finally losing the hidden kingdoms Nargothrond, Doriath, and Gondolin near the culmination of the war. When the Elves had been forced to the furthest southern reaches of Beleriand, Eärendil the Mariner, a half-elf from the House of Finwë, sailed to Valinor to ask the Valar for help.