What causes Agamemnon to sacrifice Iphigenia in Iphigenia at Aulis?

In the play Iphigenia at Aulis by Euripides, Agamemnon is compelled to sacrifice his daughter, Iphigeneia, because the Greek fleet is stranded at Aulis by calm or contrary winds.12

These unfavorable weather conditions are caused by the goddess Artemis, who prevents the expeditionary force from sailing toward Troy. To appease the goddess and secure the winds necessary to proceed with the war, Agamemnon is told he must offer his daughter as a sacrifice. To facilitate this, he lures Iphigeneia to Aulis under the false pretense that she is to be married to Achilles.1324