<p>There are <strong>no building prerequisites</strong>. The building names next to the cost indicate that you may construct the building for free, without having to fulfill the resource cost. From the <a href="https://boardgames.stackexchange.com/questions/10938/where-can-i-find-the-rules-for-7-wonders-and-its-expansions/10939#10939">rulebook, p. 4</a>:</p>

<blockquote>
  <p><strong>Free Construction (Chains):</strong>
  Some structures in Age II and Age III have, to the right of their resource 
  cost, the name of a structure of a previous age. If the player has built the structure named there during a previous Age, that  player  can  build  the  structure  for  free,  meaning  without  having  to  fulfill the resource cost.</p>
</blockquote>

<p>Since Halikarnassos allows you to construct any building in the discard pile for free, anyway, the "chained" card is irrelevant at that point. Nevertheless, you are still <a href="https://boardgames.stackexchange.com/questions/31500/can-you-use-halicarnassus-to-build-a-duplicate-card">forbidden from constructing a duplicate card</a>.</p>

CC BY-SA 3.0
2017-10-25T15:24:04.813Z
2017-10-25T15:24:04.813Z
Adama
<p>When playing with Halicarnassus A side and I build a second wonder stage, is it possible to build a structure that in its precondition cost has another structure which a player controlling Halicarnassus doesn't have built? </p>

<p>For example, to build Haven, you need to have a Forum in play.</p>

<7-wonders>
Precondition costs for structures built with Halicarnassus "build for free"?
borgmater
# Precondition costs for structures built with Halicarnassus "build for free"?

(Asked by: username_0 on 2017-10-25)

When playing with Halicarnassus A side and I build a second wonder stage, is it possible to build a structure that in its precondition cost has another structure which a player controlling Halicarnassus doesn't have built?

For example, to build Haven, you need to have a Forum in play.

**Tags:** 7-wonders


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## 1 answers

### Answer by username_1 on 2017-10-25. Score: 12 | Accepted answer

There are **no building prerequisites**. The building names next to the cost indicate that you may construct the building for free, without having to fulfill the resource cost. From the [rulebook, p. 4](https://boardgames.stackexchange.com/questions/10938/where-can-i-find-the-rules-for-7-wonders-and-its-expansions/10939#10939):

> **Free Construction (Chains):**
> Some structures in Age II and Age III have, to the right of their resource
> cost, the name of a structure of a previous age. If the player has built the structure named there during a previous Age, that player can build the structure for free, meaning without having to fulfill the resource cost.

Since Halikarnassos allows you to construct any building in the discard pile for free, anyway, the "chained" card is irrelevant at that point. Nevertheless, you are still [forbidden from constructing a duplicate card](https://boardgames.stackexchange.com/questions/31500/can-you-use-halicarnassus-to-build-a-duplicate-card).


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