Urza's Saga is the first Set released in the Urza's block, and was released in October 1998. The development code was Armadillo, the official expansion code is USG.
Urza's Saga has 350 cards, with a total of:
Urza's Saga has a storyline and thematic feel that suggest an artifact-based set, although the set was originally designed to be an enchantment-themed block. According to Mark Rosewater (one of the developers), the decision to make the storyline of the set a story about Urza was made only when the design of the set had advanced beyond the point where the mechanical focus of the set could be shifted. Rosewater considers it to contain some of the most powerful artifacts (and artifact-related cards) ever released, with many cards now banned in tournament formats.
The story of Urza's Saga and the later sets in the block are prequels to the former Tempest, Stronghold, and Exodus sets, explaining the aftermath of the Brothers' War as seen in the Antiquities expansion.
Whereas other sets have all five colors of cards referencing the same story, Urza's Saga has each of the five colors showing a different part of the storyline. Green cards detail the conflict on Argoth, which would lead to the events of theIce Age expansion. Black cards reveal Urza's failed attack on the plane Phyrexia. White cards document Urza's period of recuperation in Serra's Realm. Blue cards explain Urza's founding of an academy on Tolaria and his temporal experiments. Red cards show Urza's alliance with Shiv.
Shiv, Phyrexia, Tolaria, and Serra's Realm are some of the most iconic settings in Magic: The Gathering. Most of the story of this set is written in the book Planeswalker, though the battle of Argoth is from the end of The Brothers' Warand the founding of Tolaria and alliance with Shiv are found in Time Streams.
Urza's Saga introduced two new keywords to Magic: The Gathering gameplay.
Cycling cards allow a player to discard that card and pay a mana cost to draw a new card, effectually replacing the card with a new one. In Urza's Saga, the cost for cycling is always two generic mana, but other costs were used when it appeared in subsequent blocks.
Echo is a mechanic that requires the player to pay the casting cost for a permanent again on his/her next turn, or it must be sacrificed. Urza's Saga contained a number of "free" blue spells that allowed the player to untap the same number of lands as the card's converted mana cost upon resolution, freeing land for other use.