One of those states ( Schwarzburg-Arnstadt ) was based in Arnstadt ; it was founded in 1574 and existed until 1716 , when it fell to Schwarzburg-Sondershausen .
One of those states ( Schwarzburg-Arnstadt ) was based in Arnstadt ; it was founded in 1574 and existed until 1716 , when it became part of Schwarzburg-Sondershausen .