The prospect of reform inspired a small group of Protestant liberals in Belfast to found the Society of United Irishmen in 1791. The organisation crossed the religious divide with a membership comprising Roman Catholics, Presbyterians, Methodists, other Protestant "dissenters" groups, and some from the Protestant Ascendancy. The Society openly put forward policies of further democratic reforms and Catholic emancipation, reforms which the Irish Parliament had little intention of granting. The outbreak of war with France earlier in 1793, following the execution of Louis XVI, forced the Society underground and toward armed insurrection with French aid. The avowed intent of the United Irishmen was to "break the connection with England"; the organisation spread throughout Ireland and had at least 200,000 members by 1797. It linked up with Catholic agrarian resistance groups, known as the Defenders, who had started raiding houses for arms in early 1793. To augment their growing strength, the United Irish leadership decided to seek military help from the French revolutionary government and to postpone the rising until French troops landed in Ireland. Theobald Wolfe Tone, leader of the United Irishmen, travelled in exile from the United States to France to press the case for intervention.

Based on the above article, answer a question. How many years after raiding houses did the Defenders link up with the United Irishmen?
4