import re


def split_camel(word):
    """
    Separate any words joined in Camel case fashion using a single space.
    >>> split_camel('esseCarthaginienses')
    'esse Carthaginienses'
    >>> split_camel('urbemCertimam')
    'urbem Certimam'
    """
    m = re.match('[a-z]+[A-Z][a-z]', word)
    if m:
        _, end = m.span()
        return word[:end - 2] + ' ' + word[end - 2:]
    return word