The agency, which picked up the account following a three-way pitch, will be tasked with extending the brand's appeal into previously untapped sectors.
Ecclesiastical, which was set up in 1887 to cover churches in the event of fire, has traditionally targeted Anglican clergy.
The first project will use the strapline 'What's different - everything, what's changed - nothing' to convey the idea that although Ecclesiastical customers now have access to a wider range of products, the quality of its advice remains the same.
Ecclesiastical has already successfully expanded its specialist customer base to encompass charities, care homes, schools, nurseries and heritage properties as well as home, travel and wedding insurance. It sells its products both through brokers and direct to consumers.
The company also offers a broad range of financial services, including an ethically screened investment fund.
Its core customers are those who are seeking ethical financial advice as well as organisations that operate in the faith and third sectors.
Ecclesiastical began its drive to appeal to a wider
audience last October when it hired branding agency Corporate Edge to refresh its brand image. The revamp also saw the creation of an interactive website.
In 2006, the insurer posted its second-highest profit to date of £77.1m.