We need to translate visible text content, preserving HTML tags exactly. Only output the translation. So we need to replace English text between tags with Japanese translation, keeping tags and attributes unchanged. Also keep links text? The visible text of links should be translated, but the URL stays same. For example: (Source: Britannica) => (Source: Britannica)? The visible text "Britannica" is a proper name maybe left unchanged? Usually we translate visible text but proper names maybe remain. It says translate visible text content. The link text is "Britannica", "NMA", "Australian Dictionary of Biography", "The World According to GaWC". Those are titles, could be left as is or translated. Probably keep as is because they are proper nouns. The surrounding "Source:" should be translated. So "Source:" becomes "出典:" maybe. We'll translate. Let's translate each paragraph:

For centuries several countries have sent their prisoners to exile in convict colonies. There are a few colonies that have started in Australia. First, let’s talk about Brisbane and the reason why it was founded.

Japanese: 「何世紀