On Friday, Austin formally filed a lawsuit against the State of Texas, challenging the constitutionality of Senate Bill 4—the "sanctuary cities" bill. The city joins San Antonio, El Paso County, El Cenizo and several advocacy groups in its fight to kill the new state law that tightens the state's illegal immigration policy and threatens to remove local leaders who fail to comply with the law. The timeline below chronicles how we got from the bill's filing in the Texas Senate to the several lawsuits and protests that ensued in the wake of its passage.