The agency appointment, which was made following a competitive pitch, marks the first meaningful marketing activity for Ancestry.co.uk, which went live in the UK in 2002.
The site, which is part of the MyFamily web network, enables users to research their family history across hundreds of years by searching national census information and birth, death and marriage certificates.
Ancestry has a partnership with the National Archive to access the civil information; in return it is digitising much of the archive.
Agency Republic will handle media planning and buying and creative for the genealogy company, which, with more than 850,000 paying customers, claims to be the biggest subscription website in the world.
The UK site offers three subscription packages: annual, three-month and pay as you go. As well as being able to carry out searches, subscribers can access scanned-in copies of census documents.
Geneaology is a growing past-time in the UK, with the advent of search engines such as Google making it easier for consumers to access their family histories.
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