Simplify the following text for a Grade 8 native English-speaking person.
Original: In 1983 , he was elected president of Sinn FÃ in and became the first Sinn FÃ in MP elected to the British House of Commons since Phil Clarke and Tom Mitchell in the mid-1950s .
Simplified: In 1983 he was elected president of Sinn FÃ in and became the first Sinn FÃ in MP elected to the British House of Commons since the 1950s .