Complex sentence: Mrs Costello was involved in the War of Independence in Tuam, and she was elected to the Irish Free State Seanad Éireann as an independent member in December 1922.
Split into simpler sentences: Mrs Costello was active in the War of Independence and became a senator in the Irish Free State. She was elected to the Irish Free State Seanad Éireann as an independent member in December 1922.